Fishing Tailwaters

It still looks as if the early April trip to visit the MIL in
Tennessee is a go. I still plan on fishing one or more of the wadable
tailwater rivers in the general area. But never having fished a trout
tailwater before I'm uncertain as to how to proceed in regards to best
time to be on the water. Is the fishing generally better when the dam
discharge is causing the water to rise or is it better when its
falling? Or, instead, should I look for fishing to be better when the
levels have been stable the longest?

Any help would be appreciated.