ok, I think I like Ace's plan...because I would not have to drill the current sump. I have room for a 9" tall stand and the skimmer sitting in the 20g is 28" tall. That leaves me with a few inches to get the collection cup off the skimmer if needed.

So, Ace...with your plan all I need is a stand for the 20g long, drop one drain line from the main display tank to the 20g, skimmer drains to the 20g (in it's own container), and plumbing to drain the 20g tank to the sump, drill one hole in the 20g on the side up high and drain to a section in the sump that is before the sump's baffles.

Correct?