Drop the pan into place, climb under the car to and trace out the crossmembers with a silver sharpie. When you pull it out and flip it over you'll know exactly where to prep and drill. With thin floor pans I like to prep with a scotch-brite roloc disc opposed to grinding discs etc. It's a good time to clean up and protect the insides of the crossmembers while you have access and maybe do some addition welding where the crossmembers tie together with each other and to the inner rockers instead of them being held together solely with spot welds on tabs. I pulled the The passenger quarter glass to get it in the car and I started at the hump/brace at the trans tunnel for fitment. It seems to be where the fitment issue is. Other then that It fell in place.
