Sizes/Specs - Jackson Kayak - Whitewater Kayaks, Fishing Kayaks, Recreational Kayaks
funrunner 70 would be the right size,as it is the bigger one offered.
Zen 75 would be the right size as well.
Whitewater Kayak: Jackson Zen, River Running, Whitewater Kayaking | Jackson Kayak
after looking at the JK pages, either would work, fun runner is supposed to be a'sporty' river runner... but the Zen would be better for creeking, waterfalls, and general bigger water river running for sure. i second my opinion for the Zen as i have seen more people liking that boat around the southwest/ Colorado.... never seen anyone paddle a fun runner because in general its either playboats or creekers around here. I would love to paddle a Zen on the grand canyon, for instance, or any harder run.. i am not a class IV playboater.
as for the weight you will be totally fine. i weigh 235 and paddle a superhero and superstar. no worries!
enjoy the awesome rivers down there, i would love to visit someday......