I grew up on Santee. Had a house on Wyboo. Fished alot of club tournements, won some. Haven't fished it in 20 years, but I'll give you my 2 cents worth. Wyboo, Potato Creek, Taw Caw are NOT the best areas to fish. Like you said, its tough. Best bet is to wait until late april/may and start fishing top water. Try the flats out on the main lake headed toward Goat Island. Fish the cyprus trees/grass beds and back water ponds.
My suggestion for this time of year would be to follow the dam over to the Rocks Pond area. Lots of back water ponds over there;good fishing. Also lots of flats with cyprus trees.
Also trailer up to Packs Landing at the North end of the lake. Great fishing up there; SB/worms around the cypress trees/grass.
One of the hottest areas this time of year is in the lower lake around Angels landing. Its a good boat ride from Wyboo but worth it. Follow the dam all the way to the canal, go down the canal and turn left. Find Angels landing and go back iinto the coves, backwater ponds. You'll have lots of company.
Hope this helps. Really miss that lake. There are 30+ lbs sacks caught this time of year up there.
Good fishing.