Tid bit: I wanted to have the original 87 300D yellow style fog lights in the Depo headlights I just bought and found out it is possible to take the H3 bulb holders off the Bosch reflectors and move them over to the Depo reflectors. The holes are the same size, the units are the same dimensions, focal point is the same depth from the mounting face... it must be a standardized part to hold the H3 bulbs.
Just pry up the metal tabs on the reflectors to remove the bulb holder. Now, I've got the MBenz stock yellow glass bulb shrouds mounted over the H3's in the Depo headlight assembly.
If you leave the yellow shrouds off, and run naked H3's it's like having another set of low or high beams, depending on how you adjust height... because there's nothing blocking any of the H3 output from hitting the reflector or coming through the front. The glare off that configuration means not suitable for oncoming, just lonely roads.