I've landed the S76 with 10 degrees of pitch/roll and then seen it go to 12 deg whilst on the deck and it behaved OK, just need to be aware that if it's a wet steel deck it will slide after 10degrees in the fore/aft axis so you'll need to chock or sandbag the wheels. As for turning the AP's off or leaving them on, I think most SOP's have them off. Heave hasn't been much of a factor either as the undercarriage can take alot of punishment if you misjudge it.