Hi ~
You can cool them down as you would other N. A. colubrids ~ They are both at a breedable size now. You should definately sex the snakes before you even bother with it.
There are not alot of people in America that put forth an effort to breed most types of Watersnakes. If you purchased them here in America, you likely got babies from a wild caught gravid female. Its likely that if you bought them out of USA, they were genuine captive bred. Either way, its great to see someone giving it an honest effort! Thanks, Leo
Skin & Scales