I've tried Walker Scalp Protector. It extended my possible wear time by about +1 day.
I had expected much more improvement from it.
By "liquid skin" you mean something like the product "KP Skin Med Low-odor Liquid Bandage"?
If I understood correctly, that is just some antitranspirant. I think I purchased and tested it about a year ago, tried it only once, strange feeling on my scalp, and didn't even reduce the oil production

Note: oily skin is totally different to sweating: While sweat is rather salty water (to put it simple) which doesn't cause problems for me, oily skin produces much sebum which destruchts my tape

And yes, from the outside I tried all tipps against oil producing skin... using only seldom and little and adequate shampoo/soap etc. etc... My skin keeps being oily. I just need a fixation method which stands the oil.