That's a great size for a tank!
With 30" depth and LEDs still in development 400 w MH with T-5 supps, an expesive chioce energy wise, but is tried and true for results with SPS. Lumenarc and Lumenbrite reflectors are both excellent and I don't think either woud be a mistake. I like a 12K ReefLux bulb with a few T-5s that's a very personal choice IMO.
The MP-60s move a huge anount of water. A pair of these synced on each end with some Tunzes here and there to fill in would be really sweet. The interaction of the two distinct flow patterns is very nice. I've been mixing MP-40s and 6100s on a smaller scale for some time now and I'm very pleased. With the coin your considering spending look at the Abyzz pumps and similar DC speed controled options that are becoming available, and don't be too quick to abandon CLs with these controlable DC pumps in mind.
For a CA RX an MTC Pro Cal is a great large reactor and well priced too. A GEO kalk mixer is a good investent as well. I like to dose supplemental elements from there and use these reactors for stability. But that is because I like to tinker with my tank every day. If you don't, you may want to dose two part and deal with it weekly.
As for skimming, a big BK would make a great heart for any tank this big. If you're set on a BK, I'd say the 400 or 650 depending on how many fish is .... enough!
All this said, I've helped lay out tanks as big as 375, but only held about 640 gallons in my system from time to time under various configurations, but never in a single display tank!
Good luck with your build!