the H22 is a great engine to build all motor or turbo. Its not as common to do the H obviously compared to the B-series due to the availability of parts for the H series. but there are parts out there.
We've build mild to Full race All motor setups for the h22 and there are plenty of combinations to go with.
Common bore size we do for MOST setups are 89mm all motor. you can go bigger 90mm or so, but for reliability, we recommend sticking with 89mm unless you plan on having back up motors for a full race setup anyways.
As far as piston choice, there isnt much, we usually do a custom Arias piston for these All Motor setups. For street, we've done 12-12.5:1 compression and for full race, we have done 14-15:1 compression pistons.
the H22 is a great platform, just not as much info on it as the B-series does and thats why people are hesitant to go H series.
Wil
Exospeed Race Engines
www.exospeed.com