I left the resistor in line with the OEM style coil with my Pertronix. I looked at the waveforms on the coil with a scope and saw no reason to increase the stress on any of the parts by running the full 5A-6A through it with the way I drive.
also forgot to say... using ballast of course. 0.8 Ohms HiPo ones. I think Don sent me one of them to use with his setup
I think in fact kept using sometime the stock dual one