How thick a layer are the vaseline and baby powder supposed to be?

[SpeciesK]

I kinda thought that the vaseline was a barrier because they step in it and get stuck in the goo, so they back off. So I added more vaseline to the top inch or so of the wall of the buckey to make it like a vaseline moat on the wall. But they just ignore it I guess and walk over the top of it! Is it supposed to just be a tiny thin coating on the wall?
And the baby powder I put from the dirt up to the vaseline and I thought it worked okay but in a few spots they were walking over it so I added more, and they just climbed over all of that, plus the vaseline and got out.
So, how thick are the layers of baby powder and/or vaseline supposed to be on the walls of the bucket?

[Martialis]

Vaseline works better when combined with olive oil.

Combine rubbing alcohol with your baby powder to make it more effective.