Thanks Will! To be honest, as far as introducing the fish to the slightly salted water, I really didn't do anything. I figured it wasn't very salty so I let the bag sit in the water for a while to adjust to the temp and then I just let them go. They did fine. They've been in there for a couple weeks now. I definitely am going to add more rainbows to both tanks. Unfortunately I couldn't find the sex ratios I wanted ideally so I bought a few and am going to add more as they become available.
Chris
Chris