Planning a sump

This will be my first attempt at a sump. I picked up a 20 gallon tank today to use as a sump for my 40 gallon. The dimensions of the 20 are roughly 24x12x12.

I only need two sections one for the skimmer and one the return. At some point in the future I would like to add a refugium on it's own return pump.

The skimmer is a 65 gallon Coralife Skimmer. I think the pump is a Rio, but I'm not 100% on that since I bought the skimmer used. Will a 10" baffle be sufficient to run this skimmer?

I have a Maxi-jet 1200 I'd like to use as the return pump if possible. Should I use the Maxi or get a different pump for a return? The distance between the top edge of the sump and the top edge of the DT is 27"

Would it be possible to plumb a SCWD into the return line at some point in the future?

Witch one of these Eshopps Overflows should I use?

Any tips on noise reduction?

 

For head height you want from the water level of the sump to highest point of the return .. not the top edge of the sump.

 

I'm not sure how much water will be in the return section. Any way to find that out without having the sump full and running?