Reddit mentions of Understanding Wood Finishing: How to Select and Apply the Right Finish

It's probably not that big a deal. Get a board, sand it like you sanded your floor, put on the sealer you used and apply the stain and finish you want. In other words, reproduce what you've done on something you can throw away. Or use the floor in a closet, if you're that lucky. Before you think about sanding, contact the manufacturer of the finishing products you plan to use. Some things to consider:

Changing solvents (in this case water to something like mineral spirits) sometimes matters and sometimes doesn't. In this case, it probably doesn't matter very much, but it would be good to test it in limited area before you comit to the whole floor. If you're switching solvents, it's generally important to let it dry completely. Wood will always have some moisture. If you leave it for a day and have good ventilation in your house, it should be as dry as it's going to get, but you can test it by taping a piece of clear plastic down and leaving it overnight. If there's condensation, it's still drying. A moisture meter is more reliable, but really, if it feels damp or surprisingly cool to the touch, it's still too wet, and if it feels the same temp as everything else, it's probably dry enough.

It's very hard to prevent uneven absorption of stain around knots. How you apply the stain matters. I made a dining room table out of pine and did a lot of stain testing beforehand. Using a wood conditioner or shellac (which can also be used as a wood conditioner) mostly just made the stain lighter, and didn't substantially prevent uneven staining. The problem was wiping the stain. Any grain that was slightly more open, like around knots, collected a lot more stain as I moved the stain over the surface. Spraying with an HVLP gun made a huge difference, since all of the parts got the same amount, regardless of the grain. I used a TransTint dye stain diluted with alcohol, but there are alternatives. You could put TransTint on your floor, but if you were going to spray you'd have to mask off the lower few feet of your walls even with an HVLP gun. TransTint dyes are extremely concentrated, kind of like pen ink, so you can tint without significantly diluting finishes.

One option is to seal the wood so it doesn't absorb any stain, and then use a toning approach like is used in mass-produced furniture. Basically, you can tint the finish itself, and then as you add layers, it gets darker. It's not splotchy, because the floor is already sealed. The downside is you lose some clarity, since you are looking at the wood through a tinted film (polyurethane or whatever).

I'm not sure what brand you're using, but I'm not a fan of the Home Depot and Lowe's finishing products. I've been repeatedly disappointed by Minwax stains in particular. Their floor finishes are okay, but you can do better. Something like Bona.

My opinions are based on this book and experience, some with refinishing floors, more with woodworking.

Do you have any specific Flexnor book in mind, are they all the same, or should someone read them all:

• Wood Finishing 101: The Step-by-Step Guide
  
• Understanding Wood Finishing: How to Select and Apply the Right Finish
  
• Applying Finishes: Techniques, Tips, and Problem-Solving Tricks
  
  ...Are the Flexner books mostly about brushing/rubbing on finishes? Any recommendations for good books on spraying a finish for a beginner? Like explaining the various setups (HVLP, etc.) and the finishes available?