hehehe, given how our particular AH-brand of B-25 soaks up bullets like a sponge, you might need to add an ammo multiplier of 3x or 4x for the Ki-43s to stand a chance!
I think it will be OK. In the past, we ran this event with D3A's standing in for the Ki-43, and it worked well. It is balanced by various factors: B-25C's (no tail gun), no formations, but more allies than axis (to give bomber pilots good chance to make it to target at least sometimes), no dot radar, and no sector counters below 500 ft.
In the past, it's been quite a fun fight.