There was a thread some time ago/year of two about adding a washer to shim the bulb back to narrow the difference between high and low beam.
I used two "O" rings on each bulb between the bulb base and the holder / reflecter base. From my National "O" ring kit. A #217 o ring fits inside a #221 o ring, used o rings cause I didn't have the correct size washers, but the 2 o rings are like a washer.
This narrowed the change from high to low so that both high and low are usable.
Also tryed Siverstar bulbs at $30 each, on my sled they burnt out the 1st season and burnt out the 2nd season on the wifes sled. They are brighter.