So, today I bought a 102" whip, mounted it on my left front jack mount, used my coax I already had on the truck, and everything seems hunky-dorey! My SWR's are below 1. 0 on all checks. I have the whip mounted on a 6" spring on top of the mount. I plan on using tennis balls the keep the rubbing in check.
I didn't have to use any other grounding wires. I checked my jack mounts and they are grounded to the chassis, so the antenna mount is grounded to it and no other grounding was necessary.
The antenna sticks above the roof about 50". Not the 2/3 that is recommended, but it seems to be okay.
Steved, thanks for the input!
SOLER