The term "moon face" always gets a chuckle out of me. My face is naturally narrow and a little bony, so it may not affect me in the same way. My face "fills out" when I'm on, and I look better. I would argue that my face looks better when I put another 20 lbs on, too.

However, if your starting point is a round face, I can see how it could quickly develop into moon face. If serms, ais, etc, don't help, then I'd stick to androgen that are known to shed water as your best bet. Mast, Winny, etc.