G3, I don't use SI when I'm going WOT but rather 2D and sometimes combo 2D with map ( if I don't know the water ).

Regarding Guntersville, there is a lot you can look at. I would first start looking at things you can notice out of the water like rip rap, grass, laydowns, bridge pilings, floating docks and did I say grass.
You'll also want to get out on known ledges to see its reflections. I'd check out the ledges from both the deep side and shallow side.