So one thing people do is get some of those adhessive poster mounting things, and you can make such a thing out of double sided tape and cardboard. Anyway you use that to hold your object to the wall while the caulk dries. It is a glue that like a little thickness. Anything that spaces will work.
It is interesting stuff it is great where there is vibration, you can use it to seat hardware in high vibration areas, and one would think the amount left after a machine screw was down would be near zero, but it still seems to make a difference.