When using a jig and float for summer runs, you need to adjust for water conditions, just like with winters. In low, clear flows thing 1/16 ounce jigs in pale colors such as light pink and white. In high flows, like we have around here right now, I would start with my favorite winter jig - cerise 1/8 ounce.
My next choice would be hot pinkor red.

Having said the above, I do know that black has been a go-to color for many summer run fly flickers. It should work well as a jig color too.