Wish I could help. I haven't grown pie pumpkins before, but planning to next year. If no one here has an answer for you, there is a pumpkin gourd forum here. I've never used it much, but if anyone has an answer, I bet someone there would.

Here is a link that might be useful: pumpkins

Four hours at 350 degrees is a lot more than you would need to cook a pumpkin. If memory serves, I think one hour is plenty! :)

Can you fit several into the oven at the same time? Do you have a freezer where you could store the pulp? Or could you can it? I take it you now have ten left. Preparing all of them is the only way I know of that will allow you to know which are going to give you pumpkin pulp and which are going to give you spaghetti, but you're going to end up with lots of pulp, especially if they are very big. Do they all look alike on the outside?

There are many good uses for spaghetti squash, and it does retain its texture. Yes, I would write and at least let Mr. Hume know what happened. --Ilene

There are better choices of varieties for pies. I have always found those little sugar pumpkins to be a bit on the stringy side. My favorite pumpkin/squash for cooking is a long island cheese squash. Butternut is also great for pies. Then too, for whatever reason (usually weather), some years some pumpkins/squash are just stringier than others.

Rather than using a food processor, I run the baked squash/pumpking through a food mill before using it in pies. You might find you get a more consistent and acceptable texture that way.

Thanks everyone. I just sent an email to Ed Hume so will see what the response is. Baking a lot at a time sounds like a good idea but then I'd have to freeze any that were appropriate for pie after mushing them, assuming there are any that will make into pie. I've had it, tho'. Have no intention of baking any more since 75% of what I've done, so far, are not capable of being made into pie. The first pumpkin was stringy but when put through a sieve, was fine. The "spaghetti squash-type" pumpkins still had a hard texture even after going through a sieve.

Thanks for the hint for the squash as a better alternative. I may try it next year.

I cut up 2 small sugar pumpkins purchased at Trader Joes for my pumpkin pies. Baked them at 350* for an hour they were both more firm and drier than I expected them to be, but once I put them into the processor and whizzed them up the pulp was very smooth, although I did have to add a bit of cream to help with the dryness.
I even ground my spices, used cream and eggs and to tell the truth, for all the trouble the flavor and texture was so close to the canned I wouldn't do it again :(

I have been using Japanese pumpkins (Kabocha squash) as a pumpkin substitute and it is very good and very sweet.
I plan on growing some this summer.