I don't like the 6.8, because anything in 270 cal is gay laugh. As for a wildcat on the 6.8 case - the brass is somewhat hard to come by. I don't mind getting tooled up for a different cal, but the Grendel is pretty hard to beat. Never thought about the Beawolf, I'll have to look into brass for that one. Anything 20 cal is gonna be too small for deer. Are there any wildcats on the 204/222 RM case? I have a 222 RM reamer that I could bush up to 25, 6.5 or 7...
While I don't like the various oddball 458/450 brass, I thought the 45 Win Mag would work easily.

I hate chasing brass and will expect to lose 20% or so. For that reason brass has to be easy to find and cheap.

Some is Good---More is Better----Too Much is Just Right