Thanks again. I did not see the dimensions when I looked but that is me just being stupid I guess. Also, I made a mistake in my previous post. What I should have said is that the hole diameters are 10.25 and 9.25 inches. I used the 10'' and 9'' pivot holes to make my cutouts with a 1/2'' bit. The Excel sheet lists them as 260mm (10.24'') and 230mm (9.06''). So it looks like I could have made the inner (through) hole slightly smaller but I am still very happy with the results I have.
Yes I am still going to try the MCM amp. I have 2 of them I need to use for something.
Trying really hard to understand basic principles of speaker building . . . . failing miserably.