Tractor Supply stores give free t-clips with post purchases. The stores usually have excess because not everyone takes them - I was given a bag of 1000 last time and they wanted me to take more, but I prefer the plastic clips:
I use t-posts, Tenax plastic fence, and Zareba yellow plastic insulators as clips. Those are nice since they clip on and off quick. Rabbits and squirrels chew right through the bottom of the plastic fence, but it’s great for deer. It’s quick to put up and take down.
Sounds like a cool spot you have!
I fence some of my trees individually with the Dalen’s sturdy plastic dear fence. It’s almost “invisible” from across the yard, if that matters to you. It’s 7 ft tall, so when I lift it off ground, it keeps the deer and elk at bay. I agree with the advice on making larger enclosures- I think this makes sense whether you want to keep trees small or if you want to train branches to be above the animal’s reach. That zone within a few feet of the trunk should be nibble free as you train the scaffold branches.
I’d also suggest that you plan on a way to open up the enclosure- I use the releasable UV resistant zip ties (8”) to attach end to a post. Easy access helps with training, trimming, weeding, mulching, etc.
I’ve never found a way to completely exclude animals; better to set my expectations that I’m going to share the harvest. More about keeping trees healthy so I get fruit.
Good luck with your orchard!
Thanks, very neat spot. If I can keep the animals mostly satisfied with something else and wind coming off the water doesn’t bother them I should be fine. 
After reading this and elsewhere I think I am going to try the 5 ft fence I have on hand in a roughly 40" diameter. It’s very heavy duty being 10 and 12ga wire plus I already have it. The “almost invisible” portion would be nice but as long as I keep it neat and straight everything should look good, I hope.
My hope is to keep everything above them being on B.118 and MM.111 rootstocks.
For sure. Good tip on easy access. I plan to use spruce/pine mulch at the base after removing the top layer of field growth so I should be okay year one. It’s when that grow wants to return I’ll have to be careful.
That is a good line of thinking on the sharing crop. Tree health is important. Plus I’ll never win over the red squirrels. 
Downlake,
I started with fence circles around my trees. Just about imposable to prune them properly. The deer would stand on their hind legs and nibble away!
I put up an electric fence. I used the wire fence cut in half to be the bottom part of the e-fence. With the first hot being 2 inches above the wire fence. Going up 5 ft was plenty to stop the deer and raccoons.
My T posts are 20+ ft a part… I tensioned the wire fence from corner posts.
Our trees are open center with scaffolds starting at 15 inches off the ground. Easy picking, easy spraying and pruning. glad I invested the time to secure the trees. E-fence parts are not expensive. Deer and 'coons learn real quick to look elsewhere.
