1 hr. trimming down the bottom side edge of the fuel tank.  Also continued contemplation of how exactly to test the tank...

Straightedge lined up (5mm below the cut line).  Lots of clamps because I do not want that guide to move...

As I cut I move the clamps out of the way and put it behind the cut (far enough to be able to put the nibbler in straight).

And it done!  Filed and deburred for a straight and clean line.

NEXT SESSION:

1. Further contemplation on testing the tank...
2. But, if it turns out I need to buy things to do that, I will move onto the next thing I can do to not lose time.  Perhaps putting in the M4 Rivnuts for the landing light mount.