i run one of his water pumps on my 26. i had alot of trouble controlling water temps until i set up the bleeds in the head. i'm yet to spend time restricting the top hose and playing with pulley diameter to get the right block preasure, but as i'm not having problems with temps any more, it could be a while.
john is an extremely smart man judging by the couple of conversations if had with him, i'd love to talk to him more but he's always extremely busy. if you have the time and money, you should try his ideas, you'll learn heaps.