"Then when I'm applying a finish, be it Tung Oil, Antique Oil, or just BLO, I wet sand with the liquid finish I'm applying, usually starting with the second application of the finish. That's what generates the superfine dust/oil mixture that fills the pores in the grain. Of course there are several other ways to fill the pores (rottenstone and BLO or even commercial wood filler in the shade that you want). "
That is an excellent tip! I have always hated applying a finish, but with revitalizing some stocks recently, I have to do it. I have just skipped the pore filling process, but your tip makes sense here.
I have filled voids mixing the fine dust with epoxy, back in the day of cabinet making. It was a quick way to fix a problem without compromising the finished product.