To continue with the engine I needed a ring compressor. I thought the assembly video said one came with the kit, but there was none to be found, so I need to go to NAPA tomorrow.
So in the meantime I removed the mount and all the wires I had installed for the headset jacks so I could take them to my work bench.
Use my cutoff wheel at slow speed to cut off the centering tabs on all 4 jacks. If you don't do this then the tabs will contact the metal of whatever your mounted in, and the jacks won't be isolated from the fuselage.
Inlarged the holes in my mount to 1/2" dia with a unibit (photo #2), and installed a flat grommet from below, and a shouldered grommet to fill the hole from above (upper part of photo #2).
Put all the jacks back in, and reinstalled the mount and the wires in the fuselage.
Using cut-off wheel to remove the centering tab on the jacks
Enlarged hole at bottom. At top, shouldered gromet to isolate jacks.