Good to hear you’ve already thought through the issues.
Is your soil the type that responds well to gypsum? I finally realized that the soil at my house isn’t just clay - it’s sodic clay and adding massive amounts of gypsum has turned it into something you can stick your hand into.
That’s your assumption.
The Aluminum salts can be phytotoxic, esp. in non-alkaline soils.
Bleedingdirt, the current line of thinking is not to amend your hole. Instead, plant in your native soil and top dress. We chatted about this in another thread on our forum, and one of our list members has photos as to why it’s just not a good idea. You create this “basin” effect.
I think this is poor as general advice. It depends on the soil in question.
I think the bathtub effect happens when you dig a hole the exact same size as the container and then backfill with compost. Even worse is to dig deeper and fill up with compost.
My approach is different. The compost is mixed well with the native soil and the tree is planted higher than grade. I also top dress with compost and wood chips away from the root ball area. Worms move in and carry the organic matter down attracting roots there.
Richard, you would be wrong in your assumption. It is not poor as general advice, and is the current methodology and thinking, now. Trees will learn to live in their native soils:
https://www.arborday.org/trees/planting/bare-root.cfm
http://www.sustainable-gardening.com/plants/shrubs-and-trees/time-to-bust-this-myth-do-not-amend-soil-when-planting-trees
http://www.ugaurbanag.com/content/better-way-plant-shrubs-and-trees
Bleeding dirt, it can still happen, but hopefully with enough native soil, your tree roots will try to venture out. Truly, you just do not need to do that. You should, instead, be top dressing and allowing the nutrients to percolate down (like Mother Nature does). I don’t think worms really carry organic materials with them, more than ingest them, then poop them out as castings? Maybe we’re saying the same thing 
Now, if you have really heavy clay soil, certainly it is wise to plant your tree (or any plant) on a mound. But as far as amending the hole, it is now considered to not help the tree, and possibly cause root circling. We have a nice thread in this forum about one of our list members who dug their tree up they had planted in a partially amended hole. Sean posted it, and you might want to read through this thread:
Patty S.
Wow Patty, nice post. That thread is really interesting - an eye opener for sure!
You’re very welcome, bleeding. I was a big hole amender for years. But after reading a fair amount of corroborating research, this concept really has fallen out of favor, and the research shows it can do more harm than good in almost all cases. Really, the only time researchers and the experts are saying to amend, is if you’re needing to amend ALL your soil. Such as when you fill a raised planter bed. Or, if all your topsoil has been scraped away in lot grading. So, this one is well documented.
Here’s my 4 in 1 potted Cherry tree which I dug up in January. I think I had amended it. The root ball looks rich but it could just be the potting mix. I wish I had washed the soil off to check the roots.
Before this discussion, I’d already amended the hole. No way to take the compost out so I just have to play along.
This morning I headed off to my friend’s house with a 25 gallon container hoping to wrestle a giant root ball into it. I started by digging a trench along the drip line.
The root ball was surprisingly small. I pruned very few feeder roots. I trimmed off all lower branches so I could get closer. I also pruned back the waterspouts heavily. They had nasty 2 inch long thorns.
I tried lifting the tree gently with my shovel underneath but I felt a lot of resistance. At this point, I got my fingers in in search for the anchoring roots. I found 5 thick roots that went straight down into the ground. I tried to dig them out gently.
But then I got a stern reminder from my wife about the trip to the zoo planned this morning. Awww crap…I forgot completely. Now I had to prune out these roots and I was left with a very small root ball. So much so that I ended up holding the tree mostly by the thick trunk.
I drove back home and placed the tree in my wheeled cart. I then dumped a cubic foot of chicken manure compost on the roots and watered it in with a bucketful of water.
As soon as I got back home, I planted the tree in a mound as I had planned. I watered it thoroughly and here’s the final result. Should I prune it some more?
I think you’re fine. You may want to provide some filtered light for a while, to help with transpiration and water loss through the leaves to help curb the transplant shock. I probably would not have dropped down all the chicken manure - an awful lot of N. Better to just water in well. Once the tree shows signs of recovering, consider adding more amendments like chicken manure. If you feel compelled to fertilize now, a low N fertilizer is probably the best choice to promote root growth and re-establishment versus vegetative growth. The deep roots are the tap roots, they’ll grow back. And, make sure those watersprouts were not actually coming from below the graft. If so, monitor for those, and rub them off as soon as you see them sprout, since they would be rootstock, and not the cultivar. Watersprouts above the graft line of course are the cultivar and yes, they can have some wicked thorns. They do subside, but I think a good idea to prune them back, so the tree sort of “forgets” about that adventitious growth to focus on root re-establishment. I think you did a very nice job.
Thanks for the reply Patty. The chicken manure compost smelled very earthy. I hope it doesn’t burn the roots. 
I also added it on top, I did not mix it in. Most of it is the border of the berm.
I also don’t plan on adding amendments for at least a month. The tree looked a bit nutrient deficient at my friend’s house. I have a box of Dr Earth waiting for it next month.
The pic is probably not clear but I can see the graft line clearly, no suckers.
Well, hopefully the manure has broken down and composted itself, some. And, not sure that’s your graft line on the tree. I think it’s probably above that red arrow, at a diagonal, where the tree begins to branch out. In any event, if those water sprouts were above the branching, then they are, indeed, water sprouts. Nothing to worry about, I usually recommend to folks to simply prune them to the edge of the canopy. They’ll settle down and produce fruit. Just a sign of a healthy, happy tree.
I just checked and you are right again. The graft union is where all the main branches originate.
Well done!!!
Thanks Patty!
Here it is today. Good growth and lots of blossoms. One tiny fruit managed to hang on to the tree last winter. It was very tarty so I probably picked it too early. But it had a ton of seeds. 
I wonder what variety it is.
Here’s the tree today. Fruit started changing color last week. Any idea what variety it is? @hoosierquilt?
