good kayak for a big guy

FWIW,
I'm 6'2" and 250lbs and would have to say I do pretty well in the Trident-15 and for extra capacity the Ultra-4.7 is more than enough. Try them all, and again get what is best for you and only you ... Than buy a really good seat ... You'll thank me for that one

See Ya Soon,
Eric / Yakhopper

I weigh about the same as you but shorter by a few inches.  The trident 15 is great, but I would recommend a rudder.  I tried paddling the Big Game, but it was a barge to paddle.  Having internal storage right in front of you will save your gear when (not if) you crash in a surf landing/launch.