Took the plunge, no pun intended, and cut the outboard bay for the aux fuel tank. I used a cordless Dremel-style tool (Bosch) and cut out the panel using a cutoff wheel. The blue tape was a guide and it was about 1/8th inch from the final line. It went relatively quick taking only about 10 minutes to cut out the panel. There was a LOT of aluminum dust so I wore a mask. The disk was turining a bit slower so I didn't overhear and distort the edges. Once that was done, I put some cardboard into the void to help catch some of the debris and cleaned up the edges to the final dimension using a pneumatic sander, die grinder with a scotchbrite wheel and vixen file. That took about 90 minutes until I figured out which tool/process worked the best and that combination worked for me.