Welcome to kayaking.
I'm a bigun also but not as tall I paddle an older Dagger Honcho. I'm 5'11 240 sz 11 the seat is set in the middle setting and I have about 6'' of foam filling the foot well up so I can touch, I think it would be a fit for your height but they are kind of hard to come by and kind of tippy for a new paddler. I spend alot of time swimming while I am learning to roll but it is a great River Runner/ Surfer for my size.
I personaly would tell you to stay away from a Nomad as it has a round bottom while all the other boats listed have a flatter bottom to a new paddler that means eazyer to turn.
Dagger GT 8.1
Wavesport Super EZ it felt huge to me.
Alot lot of the local Shops have demo boats go talk to someone and try a few more you'll find a fit.
Confluence Kayak - Don or Jon
Mountain Mizer - Gary
Alpine Kayak - Mark
I dont know if you have heard of us, we are a group of Newbies, Rustys and Class 2&3 boaters from on the Front Range.
There is always someone from the group out paddling something mellowish somewhere, days, nights and weekends. Check out the link and join us for some fun, roll practice or maybe even a swim!!!