Minor "bug" with the addon: If you have the mod VScript Survivor Manager (VSSM) enabled it will automatically fill in the missing two player slots with bots, effectively making the mode 4 players instead of the intended 2 players. Not really something that you can fix, just warning you and others in advance. Just disable VSSM whenever you play this mutation.

I'm a soloist, but this will do

I haven't tried that mod, however, as far as I know, they won't stack, instead, one of the two will take priority over the other (most likely the better reserve ammo will override this mutation's values, but I can't say for sure without trying it).

question, for the reserve ammo will it also increase the number if i have the better reserve ammo mod?