I have STiTCH87's 40 breeder now and love it. I actually fixed the noisy overflow issue by reducing the the pipe from 1-1/2" to 1" right after the elbow and only running 250 gph through it. You only need 3-5X through the sump and rely on powerheads for in-tank flow. The large pipe with not a lot of water going through in and splashing makes a lot noise. A 700 gph overflow on a 40B is way to big for that application. I would have gone with the Super Nano Dientes 300 gph overflow. IMO you want to put 75% of the overflow's capacity through it so it won't be noisy.
I have seen some GC tanks that the silicone is sloppy and others that are fine, it's a crap shoot from what I've read. And you don't get to inspect it until you meet the delivery truck and it's already paid for! The rimless ones seem to be better. Would I have bought my tank from CG knowing it could be a crap shoot on the neatness of the silicone with it already being paid for at pick up? Probably not.
https://www.youtube.com/watch?v=6VYPFvLwqhc