Ideal size for a lightweight?

So im 6' tall, and about 140 lbs. Ive been eating my ass off for 6 months and went from 132 lbs to 140 lbs. Im just questioning how far to stray from my natural weight? I have no problem being a 6 foot lightwieght but is that a disadvantage. Ive seen guys who are 5'7 and looks like body builders who weigh 136 lbs. They look like savages, and my tall skinny ass looks like nothing compared to them. Dont get me wrong I have muscle but its just spread over a 6' frame. I have a very high metabolism and going up another 10 lbs is not an option.

140 lbs spread over a 6' frame bad?
Should I try to go a little heavier?

Thanks.