how do you do it? if you mount it with the bars flush to the joists, then the strapping takes up the space between the flat part of the light and the lip, which would set the lip of the light flush with the wrong side of the sheetrock once it goes up. do you have to mount it like that and then kind of pull the can down some? or do you leave it alone and let the trim piece take up the extra space. I am slightly confused as the instructions on the lights are horrid. or is there some other way? maybe strap a square around the hole where the light goes and screw into the strapping some? or am i looking at this all wrong. thank you. you guys have been quite helpful on my other questions