R180 as well would be the ideal situation. That has little to do with the backing plate in this scenario though.
The solution to run the R180 would either be a hub conversion which I already determined would be possible but not a direct plug and play solution. Or the other solution is Spec B axles with BE/BH outer stubs which is the way I would likely go.
I'll still end up running an R180 but will have to go with an adapter bracket because it is more cost effective.