Sump design help...

[MikeP]

About to have a sump built for my 190g. It will be 60g (48Lx18Wx16H) but will run at 37g. I'm trying to figure out what size my refugium and return sections should be (the skimmer section is big enough for the skimmer and thats it). I have 31.5 inches left in length for the fuge and return. My first thought was the fuge would be 18.5in and the return would be 13in (baffles are 10in high by the way). I have read that the fuge should be as big as possible but I've also read that the return needs to be a decent size too. I have seen a few sumps though that have a rather small return section. I'm leaning towards making the fuge bigger. Are there drawbacks to having a smaller return section? I need this thing built right the first time so I want to be sure of the design. What do you guys have under your tanks?

Thanks for any advice

PS I plan to use an internal pump but the sump will be drilled so that I can use an external pump if I want in the future.