The sump/refugium I ordered online with my dimensions. I ordered it with their design but modified everything except for the four walls and bottom. The plumbing I did myself (many trips to Lowe's in the planning/purchasing piece and ended up returning half of what I bought due to design changes originating from restrictions in space under the tank (it looks like a lot of space until you put a large sump in there...). The whole thing has taken 21 days from time of tank purchase (and I'm only 33% done), but much longer from original thought about upgrading (I went to the Georgia Aquarium when I was in Atlanta for the Final Four in April so that got me thinking...). The sump part of the process has taken two weeks due to being a virgin with working acrylics (running out of cement). I could have been done in three to four days. You live and you learn or as they say...C'est la vie...
but I'd rather take my time and do it right. One of the things this hobby teaches you is that mistakes are constly in more ways than cash.