It's been my experience that a lighter model will handle gusty winds just fine IF it's clean aerodynamically and has it's balance point to the rear of the acceptable range.

By clean aerodynamically I mean a low camber or symetrical airfoil that's not too thick on a model that doesn't have gobs of frontal area and fat wheels and such.

A couple of my most memorable days were dynamic soaring an old aileron 2 meter glider on a couple of blustery days. It was a thermal glider with no added ballast and it handled great even if it DID need lots of my attention. Some extra down trim kept the speed up and the light weight of the model ensured that the control response was crisp.

I've also flown heavy models that did not have that nice crisp response and even tended to overshoot on some planes of motion thanks, I assume, to the weight. No thanks, not for me.