How many coats of tung oil do you suggest on the floorboard? I see some cars that look like they have used polyurethane or something of that nature. I would like to get that look on my floorboards. I have put 3 coats on so far and it just looks like it is soaking that stuff in. It is just minwax tung oil. Not the Formsby high gloss. Does that make a difference? Thanks is advance!