challenger T/A spoiler on deck lid with no cutouts

Has anyone installed one of these spoilers on a 70 deck lid that doesnt have the factory cutouts underneath for the attachment hardware? How did you do it? I need some ideas. Thanks, Dan

I made the cut outs with a air driven cut off wheel.
used a pen type majic marker.
Did the same with the wing on the dart sport.
Marked where the trunk was pulled it off placed it on a comforter on the ground and went to town.