I'd forget the steel wool, it breaks apart and leaves little tiny bits in your finish. I wouldn't worry about doing anything between your first several coats, try to build it up a bit first. But then that's how i did my tung oil finish, never used tru-oil, so maybe thats diferent. Still, steel wool is a nightmare.
In fact with pure tung oil, i didn't do anything till all the tung oil was on, then I buffed it out to a brilliant shine and baby's butt feel. Not that I'm into feeling baby's butts mind you