I honestly went by looks lol I might re-adjust after

 

Why do you need a full tank of gas to adjust the headlights? O_O????

 

I read around it suggests a full or half tank, just because of the way the car is balanced... but because the gas tank is in the centre of the Monte's I don't think it's a big deal it would be more so if the tank was in the very back lifting up the car's front aiming it more in other drivers eyes

 

I too am curious to see what this mystery mod is :p
I've had these headlights almost a year now, and love them.
I had to adjust mine as well, just went with what looked good to me, maybe i should do it more precisely

 

I am looking for halos for my car but I cant find any for an 05 anywhere!

 

they dont make em for 6th gens