While working on my home built Les Paul Bass I've come up with a simple solution to cure the tilt of the Tune-O-Matic bridge.
The tilt has two causes.
The first is the loose fit of the screw parts that go into the inserts.
The second is the loose fit of the slotted part where the actual bridge sits on. Often this part is damaged because the tiny hex screws at the tail end of the bridge weren't properly loosened before adjusting the bridge height.
Both these loose fits add up to a wiggling bridge and a (huge) tilt when you tighten the strings.
Anyway, I thought of a simple and cheap solution that can easily be removed if it doesn't work for you.
Pipefitters use this very flexable non adhesive white tape to make the connection for water pipes and gas pipes a secure a tight fit. A roll of this stuff cost less than a dollar/euro.
Simply wrap some around the screw part of the stud. Pull it tight when you wrap it. Just about 5 cm is enough.
Do the same with the slotted part where the bridge slides over.
Don't forget to tighten the hex screws at the back of the bridge after you've set the bridge to the right height!
