I want to adjust my Koni Struts in the rear without having to drop the suspension to access the top of the strut. What can I use to get into that small hole in the strut housing, or do I need to cut a notch in the strut tower to access that knob.

I have the Koni's, what Idid was modify the "White Knob" that comes with them. I just ground down the lip on the edge of the knob with my bench grinder. That gives about 1/2 to 3/4 inches more depth...
For the fronts, since my SHO SHOP strut tower braces got in the way, I just extended the length with some plastic...both ugly, but both effective.....cheap too!