30g Topre's are crazy light. They are really good for pinky fingers, but honestly, I dunno about a whole board full of them.
I think the ergo-weighted silent RealForce really does a great job of mixing the 30g's and the 45g's. Those Topre guys really put some thought into designing that keyboard, and it really works. It's not the most popular Topre keyboard though for some reason. I guess it is kind of funky with the different weights for different fingers, but like I said, it works. The uniform 45g and 55g RealForce keyboards are great too. I love them all, tbh. My favorite switches however, are the silent 45g's on my HHKB Pro 2 Type-S. I still haven't tried a 55g modded HHKB, which people tell me is teh t!ts, so maybe I need to try that soon.