Your stock coil will be barely enough to power one of the 35w bulbs, and that's with no tail light or a low wattage LED tail light. I think the stock headlight bulb was 30w.
FWIW, I dual sported a '90 and had a battery installed. The charging system could not keep up, and running a DOT legal 55w headlight would drain the battery fast anytime the light was on.
If you try to power two x 35w bulbs with your stock lighting coil, you won't even get a dim glow.
FWIW, on the '89 without the voltage regulator, the tail light bulb was what usually blew.