I personally don't think that weight or height make a difference. Every body build has its inherent pro's and con's, and those little "points" that you have to fine tune. I personally am about the shortest person in our group, standing a hair over five-two, and for lack of a better word-pudgy
I can still roll and break fall like and fly through the air like the devil when the situation calls for it. Granted I'm on my toes ( lit.) as uke because Nage is generally 5 + inches taller then me. I'm also one of the only two women in the T/R class, so there is the natural strength and center difference ( but that's another thread for another day).
I would think as a taller person you would have to shorten your stride between you and your partner during some techniques. You'd have to stoop a bit for shorter Nages like me
Overall I wouldn't worry about the build issue, simply have fun training.
Regards,
Kaitlin