CRAP! Need core support help.

[THE "10" SILVERADO]

Decided to change my core support bushings since I had everything already disassembled. I went to poly cab mounts a while back and I still had the core support bushings sitting around. Well, unbolted everything and was able to squeeze the core support up to allow room to remove the old bushings and put the new ones in (pic one). After the new bushings were in I tried to line up the bolts on the fender w/ the core support and I for the life of me cannot get them to line up at all. I got one side once, but the other side was so off I figured that I needed to get all of the bolts started before tightening down. I don't know but I'm pissed because I can't get it to work and I spent over 3 hours messing with it. The top of the core support is also scraping the bottom lip of the fenders at the top so I got a constant SCREEECH everytime I messed with it. I really need help on how to fix this or what to do because I can't figure it out myself.............