OK, I guess I'm on my own.

Well, I've done a bunch of research - and everything I've read says the more/bigger the holes, the better - for cutting down on noise. So, I'm thinking of 4 1-1/2" holes. I'll put the weir at the same height as the overflow on the old ones from Oceanic. Hope it works.

Anyone have a good source of glass for my calfo?