4 Headlights or 2 Headlights; opinions needed.

Normally you can get more light out of the same wattage filament by using a larger reflector. I discovered this way way back when we used landing lights. 4537's used to be less than 4 bucks in the 70's, and you could modify them (PAR46) to fit quad lamp setups.

There were 3 similar lamps, PAR36, the 46, and the 56. All three used 100W filaments, but the light output was a bunch more for the larger PAR56 (Same as larger single headlamps)