My taper (5/3/35) and a uniform taper (4/4/4/4) run close--or equal--to an 8 ohms impedance. I personally would not suggest that you do what you are thinking as it would make a line array sound like a MTM and eliminate most of the near field array effects that I like. Plus if you are using my passive Needles crossover for your speaker, then it would need a change. On tapering I usually suggest no more than a 2:1 ratio for my tastes.

Jim