I'm new to forum, and new to SS riding, but been cycling for a long time & at 5'11" & 225lb & 32" inseam, I suppose I qualify as a Clyde. I agree with City Smasher - if you're already cycling & planning to do mostly flatlanding like you described, go with the fixed gear - it's a great workout even at moderate speed/paces & the Dawes & other bikes of that level (the Motobecane, etc.) are a great way to get started without spending a ton of cash. Maybe opt for a flip/flop with fixed & free "just in case" - just another option.