I haven't used an H2, but I would think AT853s (CMC4) > battery box > line in should work fine without brickwalling. That's how I generally run with my R09. If you just bought the H2 and can return it to the store for a full refund, maybe it's a good idea to do that and buy the R09HR. If you can't return the H2, and you have to try to sell it at a loss, I would try it before I declared it problematic.
Don't wait until you go to the $200 Rolling Stones show to try it... try it at some local bar.