Have a look at Dave Teubner's (dteubner on RBW) site, he used to dive a Ray before he got his Sports Kiss, and has done quite a bit of work on flow rates, jets, etc etc etc...
He's a very smart man...
Research etc
I think the one you want is loop 02 percentage calculator for SCR's... But i'm sure you'll find some of the others usefull too...
