Based on my experience(and some advise from the retired sifu Mr Turbo Sang), the maximum safe limit boosting on NA / stock factory internals not design for FI is 0.6 bar. To be on the safe side with stock internals, you may start with lower boosting, and gradually
increased if there is no sign of internals giving up...lol.
Leakage is kiddo stuff but dealing with pistons, crankshaft, bearing, gearbox fault is quite a headache.
Btw, H22a is quite torquey in stock form compare to other B or K series honda engine which is more of a smooth operator at redline.