So, on a four headlight system, the way I overcame the switch from high beam to low beam or vice versa, lag in brightness was to install a relay that I have on a GMC pickup, available from Summit or other places. It keeps the low beams on on high, thus retaining full brightness of these lights when switching back and forth. Its a non issue with other vehicles when the high beams are on because you will be dimming anyway, plus it increases the high beam lighting pattern. I have done this in on a truck, motorcycle and car now. Mine are just the $35 eBay sets, and I have had them 8 years without a failure until recently. On the car, I have relays to get voltage from the battery taking the load off of the headlight switch. Mine is a homemade relay setup, not as nice as the ones with soldered terminals etc that can be purchased on the forum or online. I used a terminal block with relay plug-ins.