bodyweight squats would be fine if you really are worried about putting on weight. However, i strongly recommend doing heavy weight squats. It's really easy to monitor if you think you're getting too big. You'll be losing fat anyway. Heaps of guys would love to get big thighs but they don't because it's not that easy to put on weight. Your thighs will get bigger with bodyweight squats anyway if you did them enough. also the bodyweight squats aren't really gonna benefit your other lifts as much as heavy squats.