Well, paint me with gasoline cause I'm gonna get flamed but—WHY WHY WHY?
Briteboxes and all aside (and I'm assuming you have single bulbs), these bulbs were engineered to have ONE filament lit at a time. I'm uncomfortable that the OEM harness can drain the ground return for 2 lit filaments simultaneously anyway. The heatsoak in the bulb envelope IMHO will greatly shorten bulb life anyway. If you have or convert to twin bulb housings then you could light the brightest filament on low-beam, switch down on the twin filament (low beam bulb) and enable a relay to light the high-beam bulbs brightest filament as well:
low beam 55W + 0W 0W + 55W
High beam 35W + 55W 55W + 35W
Using the NHTSA approved wattages - other bulbs are out there.
This requires at least 2 relays and additional wiring - and quad bulb housings.