Thanks Merlin, I really appreciate your input. I ordered the jacks from E-trailer, and in their review/installation videos they recommended using self tapping screws, which is why I planned on that. And I'm just using them for stabilizing, not leveling. Check out these videos if you get a minute, and I'd love to hear what you think. Thanks, Tim
at 2:40 in this video: https://www.etrailer.com/Camper-Jacks/etrailer/TJSCHD-24-4.html
at 6:10 in this video: https://www.etrailer.com/Camper-Jacks/Ultra-Fab-Products/UF48-979002.html