Personally not a fan of cap at all. I've been riding since ~97 and finally made the switch to sidewall in 2002 after going through several delams and overall poor reliability with cap boards.
That was 10 yrs ago so things could be totally different, but boards are pricey and looking down at a fresh delam is so disheartening I'm reluctant to even risk it.
166 seems huge for your size, you should be able to get plenty of float with a smaller board, plus better responsiveness. Just rode a rocker board for the first time this spring and looooved it. Pretty pumped to get a full season of riding the rocker next year (not to mention some late season corn runs this spring/summer).