Kawasaki ninja 10r... I've got 1 and I love it, it's pretty low to the ground so u won't be up in the air like u would be on a yamaha... I have an 09 ninja 10r and I wouldn't buy anything else... Suzuki's bikes are awfull and Honda is ok but I'd buy a ninja
you'll never know until you really sit on it, everyone has a different sitting position that they're comfortable in, and every bike has a different seating position
just go to a dealership and sit on the bikes, see how you feel and think about bein in that position for a good amount of time
and yea, 600cc is a lot of power, my bike is 600cc and had a 0-60 speed of about 3.5 seconds, that's as fast as super cars
but from your weight and height, i think you'd be more comfortable on a cruiser rather than a streetbike, i have friends bigger and heavier than you that ride streetbikes and they all say that they'd rather ride a cruiser