Looks like gigampz adapters. Two S3 will run fine off the Dell 750W; expected power draw is about 700WDC (at stock speeds) and these supplies are typically capable of at least 800W. Depending how many cables you were using, 16AWG (for two cables per S3) or 18AWG (for four cables per S3) is good.
The manufacturer of those breakout boards (pmorici) supplies cables with them. Ask him for specific info and purchasing.
Yes gigampz, I've had them for a while i forgot. I will holler at him about cables thanks.
If you do not OC (in fact I'd say you need to underclock a bit) then you can run 2 S3's on one of these.
With regard to cables, I'd go for 16AWG.
I do not OC, i run stock. I think i'll run with 2 cables to each miner at 16 awg.
Thanks guys!