Dont laugh, but on my 69 bird I loosened all the nuts and rolled the window up where it should be loose in the rubber channels.. Then I taped the window in the channels and tightened the bolts, not too tight. Kind of a pre set first. Then went with the final adjustments.... Went through a few beers... Oh yea if it's a vert do it on the ground on all fours, I adjusted mine on a mid rise lift first then again after I lowered it to the ground. Body flex gotta love it...