I have used the type that has rubber around it for station wagon roof racks and side mirrors.The bare metal nutserts that i have used for window regulators and power door motors used a crimp tool made by Lisle I believe. It crimped it to the door skin like a dry wall molly.Check with some body shops that have been around for years to see what they use.

Wanted Good Woman:
Must be able to cook , clean , sew , tune engines and polish trucks. Must have old Stovebolt and garage. Please send picture of old Stovebolt and garage.