Sorry man I don't know anything about deals on Kesslers. On the NS Raptor, I have a 159. I'm 5'11" 200lbs and I have zero issues with that board it's paired with a set of Ride El Hefe's I have a size 12 boot(I wear K2 Maysis). Great in powder, excellent edge hold, stiff and kinda heavy though. Only surface I had trouble with was frozen hardpack/ice, because of the huge rocker it felt extra loose, that was my only thought but since I only rode it once on that kind of "snow" what do I know, it's my powder/tree board so it never has to deal with that shit anyways. I think you would be better off without a full rocker for boardercross however, I really think you'll appreciate some type of camber. I can't speak on the Custom, only Burton board I have is a 63 Sherlock.
When I was in the Army I knew a man who had 3 rules about sex, one of them was "quantity not quality". I really regret not asking him what 200 pound twins would classify as.