Striper need cool oxygenated water. You won't find that in the Ogeechee River in June and July. I wouldn't think you would even find any that far up even in April. Outside of down around the coast, I wouldn't think the Ogeechee holds many striper.
I've caught them as far up as Louisville all the way up into July if we are getting rains. I don't remember the name of the plugs that we use but they were are 12" long,bright and flashy......