Boy, if you have divot's that deep on the caliper "ways" where the pad sets down, you probably don't have any choice but to have them welded up, and file everything smooth.
Sounds like you have some really worn caliper body's.
Those pad retainer clips are designed to keep the pads from coming out the top of the rotor, and i don't know about this "rattle" over a rough road.
To the op.
If your buying Centric pad hold down clips, then in my experience they have to be bent down somewhat for proper usage.
You can easily figure it out when you set pads down into the caliper.
View attachment 1715360037