I found Sherwin Williams has a high gloss latex enamel floor paint in black that goes both indoors and out and started applying it with a brush around the outside of the room. And then switched to a mini roller and rolled the rest of the floor. The paint guy suggested rolling as much of the floor as possible to avoid having brush strokes show. He was right, the paint is very thick and brushing it all on would ruin the smooth gloss look I wanted.
The first coat of paint rolled on quickly but was a blotchy, scary mess. I was starting to wonder if I should have stopped with the sanding and doused the whole thing with grey stain.
But after two more coats, the paint had finally covered all of the thin areas. It took more than a week for the floor to "not feel tacky", which really surprized me. I have never experienced this from latex paint before.
Afraid that chairs might scratch the finish off again, we ordered the herringbone sisal look carpet squares from Flor and put them under the table and chair area in an alternating direction pattern, making sure that there is carpet under the chairs even when they're pulled out to sit down. Nice thing about the floor being squeeky clean and I guess not totally cured, we didn't have to use the adhesive strips that came with the carpet tiles. The finish gripped them tightly. Just hope I don't have to take them up anytime soon. We just love the look. Everything just popps in the room now.