I am sure someone will know more then I do, BUT i was told the sand traps in more moisture..and can cause root rot. I saw the grit at agway, not sure if there is one near you. Good luck !

I'll start at the bottom of the list and work my way up. :) If you delay the trim installation, you will need to caulk the gap at the wall joints, mitered joints, etc. It's best to prepare the trim, prime it, install it, fill nail holes, paint it two coats (overlap on to the wall surface a half inch) and allow it to dry. It's much easier to cut-in around the trim, especially when there's a new coat of paint around it. After the paint is dry (24 hours),lightly apply delicate surface painter's tape along the horizontal trims to avoid roller spatters from settling on it. Apply just prior to painting and remove when done. Do you need to wash the walls? Have you smoked in the house since August? If yes, then wash the walls. Has hairspray been used in the room? If yes, then wash the walls. Is there floor sanding dust on the walls? If so, use a swifter to wipe them clean. I recommend a primer over the sand washed walls. SW has a high build primer than can be rolled on. That will help hide some of the texture. If you don't mind the texture and the wall is dull and clean, then repaint it. Michael

Thank you, all. Was having computer problems and thus not able to see my question (re duplicate above) or any responses, until now. After reading and inquiring more, I stayed with the sanding at 100 grit (and am applying 2 coats of poly). I was trying to get the same effect as w/screening. My understanding is that the 2 coats will sufficiently cover any small spots/areas where I went down to the wood to get deeper scratches out. It's also all I'm able to invest at this time. Reading the can of Minwax's fast-drying poly, it says it levels well and isn't as (extremely) sensitive to stirring/not stirring (though of course I'll be doing it regularly). I believe with different people (responding to brickeye's comment) working on the same large floor, the topcoat probably matters most, - and consistent stirring for a consistent finish. What a job! 'Wish I could have had pros do it, but doing it myself, am very grateful for input of forums like this. Thanks again.

Bona Traffic HD clearly states the sanding requirements. The final cut must be 80 - 100 grit then multidisc 80-120 grit. The 60 is the MIDDLE grit level, not the end level. I would bet the 36 grit was the only disc/belt the person had in their truck. https://www.bona.com/Global/Documents/United%20States/Technical%20Data%20Sheets/TDS%20BonaTraffic%20HD%20US.pdf The application instructions for Bona Traffic HD are there for a reason. I have a STRONG suspicion the "sub" isn't a professional. S/he is just "a person with a hammer" who has been given the floor finishing as a task by the GC. I would require a wood flooring professional on the job. Bona is VERY difficult to work with. It is SOOOOO difficult that a "training weekend" is required just to get a handle on this stuff (volunteer to do training...at their own expense). Without that training, this is going to be HELL on the floor-dude(ette). And when Bona goes wrong, it goes wrong in a HURRY. And there is no fix other than another sand/refinish.