its actually the f22 that has the thin walls and doesn't do well with boost.
the trend was to take the f22 block and slap on the h22 head as a cheap alternative than buying the entire h22 swap. that's when the cylinder walls became a problem. everyone boosted their hybrid 22s like they were normal h22s and the hybrids would blow. The H22 is a stout little more... especially if it is fresh. If you're going to boost it, then you need to rebuild it. Tear it all the way down, and rebuild it the right way, you'll be so much happier in the long run.
My experience, on the rebuild, you can then get rid of some of the emissions things and re route vaccum lines to lower the chances of boost/vacuum leaks and just make things simple.
as for turbo size, it depends on the rest of the build and how you want the motor to respond. I've built a motor for a customer that didn't want to make boost until the higher RPMS so it could drive it comfortably everyday, so we were able to use a much larger turbo. I've had another one want as little turbo lag as possible, so we used a t28... it all just depends...
