You could try one whitie and one 'reddy' that's what I used to do when schumacher used white o-rings and 2 leaked like buggery!
I guess the Nortech whities are a different thing than the Schumacher ones, but low friction = more chance of leaking, you can't really have low friction and low leakage when using the same material...
(unless Nortech whities are made of a material not of this planet, which may be possible....)
