Sorry, man. Got caught up in my own ingenuity (ha, ha)
You'll find that coating the fretboard as I described brings you much closer to that 'Jaco coated fretless' sound. Highs sing more, but you'll find that you need to boost more bass than before. All things equal ( EQ, string type etc.) you'll find that you have much more treble bite. I used to have a fretless with a poly coating on the board and I have to say that the tung oil-thing has better bass response and doesn't feel "sticky" under your fingers. Hope that helps with your SOUND inquiry.