Hi,
I went through the same thing a few years ago when I started running the 265. Really spooky list to either side when running in beam and quartering seas or stiff cross winds. It took a while, but I finally got the hang of things and now really like and trust the boat. (couldn't say that when I first got it.) First, the boat is VERY sensitive to weight shifts while under way at planing speeds. Try to balance the boat with load first, and ask your passengers to stay put while under way, especially in tricky seas. Second, use the trim tabs sparingly, just a quick tap on one, then give it a few seconds to respond. (and, if like me you don't have trim indicators, remember which tab you have used) My biggest mistake was over trimming with the tabs to the point where I would have to bring the boat off plane and reset them back to fully retracted. Third, use the engine trim to find that "sweet" spot. On mine, I use about 3 bars almost all the time, certainly in following seas. In a two foot chop, I would probably still use three bars. In my opinion, the 265 can go any speed you choose in a two foot chop.
Just keep experimenting, you'll get the hang of it - there is no substitute for going out and just running this boat to get the feel of it.
BTW, mine is a 2000 265 with ox66 225's
