If the cache isn't over 8 foot, then it's almost a waste of time. 8 and over and you can find some timber holes to get into.
As far as the white goes, between 20 and 32 ft. But there's no public timber there at any level, and they heavilly enforce trespassing in that area. So you are forced hunting the river itself. If the white gets above 28 ft, then there's plenty of water in Henry gray hurricane lake. But you will really have to scout that place out and find a few different holes, because the locals will beat you to those holes. So always have backups, and carry a gps because if it's your first time, you will get lost.