Can anything be used as a good cue for trying to clip through the wall? Looks like it's possible in many spots but success seems pretty random to me.

Also, are there any other wall clips in any level that could save time in 100%?

Logic behind it, as far as I can tell, is that if you recall bonus stage of the 4,5 level (dark forest one)? You cannot jump too fast in in because Prehistorik can clip through cherry's and sandwiches despite there being a solid footing if you were to walk over them normally. Point is, it seems that when prehistorik falls, he can clip though the edges of the objects, so the trick is to kinda make him fall in the right spot on the wall, I've yet to determine a sweet spot in the middle when the most time can be saved, but can 60% of the time clip by double tapping jump button at the bottom.

this wall seem to be unique since I wasn't able to do that on any other wall in the level.