In case anyone that currently owns a 66" Vector Flight Extra 300. I didn't care for the belly pan mounting on the 66" Extra 300 from Vector Flight, but John at VF recommended this modification and it seems to be working very well for me up to this point. It saves time setting up at the air field and the potential of losing those plastic bolts:

"Dear James:

Thank you for your message. Hope things are very
well!

It is a good idea to glue the belly pan to the wing
underside. This should be done with the wing
attached to the fuselage so that the belly pan can
be installed in the correct position relative to the
wing and the fuselage. Carefully score the area of
the wing surface along the joint seam, so that the
glossy finish is removed, and then use a thin layer
of 10 minute epoxy to attach the belly pan to the
wing, making sure any excess epoxy is cleaned
promptly. Drill out two holes in the belly pan
directly above the location of the wing attaching
screws, so that the screws can be accessed from
outside the belly pan.( This step should be done
before epoxying the belly pan). Additional strength
of the joint can be obtained by covering the seams
with an iron on or self adhesive tape. Finally make
sure that the front of the belly pan is tucked in so
that rushing air cannot get under and blow it off
the airplane. Once this is done, you should not
require any additional screws to secure the belly
pan, and wing removal and installation will be a one
step process.

Good luck!!

Best regards,

John
VF