MN cab corner 6x9 speaker brackets

[blindbug]

Question: How do I go about getting a screwdriver to the outside screw on these bad boys? I got a set in, installed them (I love them)... but I only used one interior side screw on the bottom, and the top screw. For the life of me, I can't see how I can get a screw bit at the right angle to put a hole for the outer mount. This is on an 86' C-10.

I got a pair of JL Audio C2 6x9's in, once I removed the rubber magnet cover from the speaker.

I love the clearance that these give you from the belts, and that they are solid as an bull ox.