I'm running an 11x7.10-5 tire and using 10" green schedule 40 pvc. I to went through a ton of time looking for the same answer to your question and ultimately took a chance and just ordered the pipe since I already had the wheels/tires. After watching people struggle to get the pvc over the tires in several videos I was dreading putting them on but I just deflated the tire as much as possible without removing the valve core and set the pvc on the ground. Then I just kinda squeezed, pushed, folded and pulled the tire into the pvc. In all honesty it took about 3 minutes per tire and was way easier than any of the videos I had seen online using soapy water or other lubricant. I did find that I needed to inflate and reinflate the tire a few times to get the rubber to balance out better inside the pvc but overall it was very easy and so far no slipping issues.
I also bought some schedule 80 pvc that is WAY thicker than the schedule 40 so it has a slightly smaller ID that I will be trying after I wear out the current set I'm running.
I would caution you at assuming the 10" pvc can be easily purchased at hardware stores unless you go to a plumbing supply store and then be prepared to buy at least 10' of it. I had no idea how hard it would be to find around her or how expensive it was going to be but I eventually found the green stuff from an online drift trike store that I can't really recommend because they took almost a month to ship and would not respond to calls, texts or emails in that month about when they would be shipping so although they were the cheapest price I could find I likely won't ever order from them again but I don't want to post the company name incase mine was an isolated incident. The schedule 80 I got from ebay and arrived 2 days after I ordered it!
These sleeves are 7" wide for reference.
