Hey Crsaz,
Very nice tank, both of them. I to am setting up a Illuminata.
I have the ATB 840 v1.5 and love it. Its got a lot of room for growth imo. You can interchange the large and small pinwheel depending on your skimming needs. Im going to run with the small wheel until I get a frag tank and then Ill switch over to the large. Shoot the small pinwheel might even be enough to take care of 120g-150g total volume.
All I know is I have run the ATB 840 v1.5 with the large wheel and have had issues with the foam head collapsing after 4-5 days. When I switched to the small pin wheel, I got consistant skimmate and the foam head didnt collapse.
About the Vortechs. My opinion is get 1 MP40w. I have 1 also, and had 2 on my 60g (48x15x17) and it was to much flow with 2 of them. With 1 youll be able to open it up nearly full throtle and get the use out of it. IMO MP20s are a waste because they are the same size pump as the MP40 just missing the better controller. I think your tank will be fine with the MP40w and the return pump. If you have 2 MP40w on a non BareBottom tank your sand will be blowing all over if you open the pump up.
With your frag tank, just get a bunch of cheap Tunze pumps and place them under your frag racks. You shouldnt need any surface agitation unless you want it. Just have the Tunzes blowing under the frag rack and youll have some crazy random flow.
Sorry for the book, hope it helps.