I just read this entire thread and thought I would add some comments as an older pear grower. To my mind there are several misconceptions about Warren and Magness that I would like to address. I’m from Mississippi and T.O Warren was my mentor at the start of my 40-year fruit journey. I was active in NAFEX and served as president, vice president and board member. So, I was involved in the early days of the Warren introduction and the controversy about whether Warren and Magness were indeed the same pear. Several experienced fruit growers thought they were but didn’t want to upset T.O. with that idea. Both are pollen sterile and are great pears. The most recent information is that T.O. got scions from an abandoned experimental orchard in MS and that Warren is lower chill than Magness (Information from Ethan Natelson in Houston, TX). I understand that Oregon investigators have stated that there is a genetic difference, but I have not seen that in print. In addition, my observation is that Warren is a healthier tree with no trunk blight tendency like Magness. Has anyone had a Magness or Warren tree have fire blight after a hail storm? https://www.apsnet.org/publications/phytopathology/backissues/Documents/1970Articles/Phyto60n04_593.PDF
I don’t remember how long it took for the two varieties to fruit in MS but here in Sebastopol, CA my Magness tree fruited in 3 years on P. communis seedling (the only rootstock I could find the first year I lived in Sebastopol - 1998). Warren took 4 years on OHxF 513 and a mislabeled Moonglow scion grafted on calleryana took 7 years (it is either Magness or Warren - I think Warren) And yes, fruiting can be a problem for both. This year I had a great crop on Magness, good crop on the Not Moonglow and a very light fruit set on Warren. In the past, the Magness tree always set very poorly so I started hand pollinating it with Comice pollen with good success. Four years ago I grafted Comice into the tree, this year Comice bloomed and I had the best crop of Magness ever. I know, anecdotal evidence, but I’ll take it.
When to pick. They both ripen at the same time. About 10 days after Bartlett. That translates to the 3rd week in August to the first week in September here. We are an hour north of the Golden Gate in what is called the costal cool climate zone. My key to when to pick is to watch for a subtle color change to yellowish-green and then for the first fruit fall. Then I start lifting individual pears to horizontal. Let those that don’t release easily stay on the tree to size up more. I get a two-week picking window that way. If they come off, pick them and put them into the refrigerator. I like to leave them there for at least a week then bring the fruit out as you need to ripen them. A week or so on the kitchen counter is usually about right. If you don’t like the really sweet taste and buttery texture, eat them sooner. They will ripen more on the tree but I think taste better with the cold treatment. And if picked that way, the fruit will store in the refer for three months.