It's been a while since I did a floor, and I don't think I stained it...
But, for the filler/sealer, there is a resin that you can buy... You'll save your fine sawdust from the final grit, and then mix it with the resin... then you put it on with a trowel, just like grouting tiles... *
IMPORTANT NOTE* -wear a headband for that part because the sweat that drips off your forehead will leave white spots.. {
Yeah, I learned that one the hard way, and a couple of those spots didn't sand out}.
After that, the final sanding was done with a sanding screen on a rotary buffer, like the kind they use for buffing office floors.. It came out beautiful...
With Oak, you have to "grout" the entire surface, and fill
all the pores. Unless you don't mind all the pores showing... But I don't think that's a good feature on a floor. Floors should be smooth and hard.
I agree with Daddy Gloves about Sherwin Williams, I would just go down there and ask them in person... They make good stuff, and they can give you all the details about it too... It's not like going to Home Depot and asking "the guy in the paint isle", if you know what I mean. I like my local Sherwin Williams store, especially for color matching oil base stain. They're really good at it.