I don't know what our good friend Turtle1 has up his sleeve. He just asked me "What could I use to do this?", and I answered.
What he seems to be attempting is well beyond the norm of regular PC water-cooling systems, so I'm not making any assumptions at all as to what's going to work out best for him.
Given enough radiator capacity, the heat dump penalty of 2 x RD30's @ 26v can be overcome, but we're likely talking about needing 8 x PA160.1 to do that, or maybe 4 x PA120.3's, to achieve a balance point. Maybe that's what he's got? Who knows?
All I know is that from what little he described of his system so far, that it's not your usual PC water-cooling setup by a long shot, and a lot of what hes delving into doesn't apply to the standard PC water-cooler. While it's not a different set of rules, the limits are different.