You could do the radiator fitting that way as well, can't hurt.
I run 50/50
antifreeze and distilled water with a 180 t-stat drilled per Bob's instruction and have never had my temp go above 185 or so, even after idling or slow moving traffic. Unless the timing is off or something else is screwy, once you purge all of the air out, you should not have any trouble keeping it cool even without the Water Wetter.