Me too, though for multigun, I'd just grab my regular open gun and shoot major loads. As a bonus it also knocks down plates better.
Re: Erebus and carry, I'd want to do some testing. If I was a better shooter, I'd just ask them to sponsor me, then I could tell you all about it.
Alternatively, if we're already talking custom gun prices, why not fly up to Atlas in VT, get some carry ammo of one's choice, and run it through both?