Ken, you should go with the fixed sight combination that you can see best, then determine the type of spotting target that will work best for you.
Most chunk matches allow a fixed globe over the front sight, though you may run into some matches where a globed front sight is not permitted, nor the use of a shader.
As usual I'm still trying to come up with that perfect spotting target that works for me but I've yet to find it. I'll keep looking and experimenting.