You need to have samples made on your floor with at least one coat of finish added so you can see the color. Regarding photos, sometimes it’s easier to add them in the comments.

Red Oak can go pink I would use ebony it looks amazing with oak floors. the floor below is ebony stained it doesn't look black just rich and dark.

I have to agree that the custom mixing unless done is a big enough batch to do all the floors with a bit left over can be a mess. Yes you need to see the sample on your floor with your lighting.

This is a good idea of how it will look IMO make sure your lighting is all LED in 4000K before choosing any colors.

Thank you so much for each of the suggestions and advice! (The generosity on this Board with everyone's time and sharing expertise is amazing and greatly appreciated!) The floors will have a satin water base finish and not oil base. Will a water base finish also change the color of the floor and add to the importance of this decision? I really appreciate the suggestions not to mix stain colors! We will have all of the floors in the house stained (upstairs also), so I can now see why blending stains would probably really create a problem! So it looks like we will be choosing between Duraseal Provincial, Special Walnut, or Chestnut (on red oak) . We're anxious to change the existing orange floors and are shooting for a medium brown tone. The house is all whites and light colors. Big decision!!! Thank you again!

Water based won’t amber the way that oil does but will still alter the depth of the color. Don’t rush the decision! When you get closer to a color you like get larger samples made in a couple different places so you can really compare.

Apply Provinicial over red oak. You will get Special walnut, which is a brown with red hue. Apply Special Walnut or Chest nut over red oak. It's going to be red.

Wow! THANK YOU, Hallett & Co - and G&S Floor Service!!!!!!! Both notes are extremely helpful and just what I needed to hear to help wrap up his decision. Really appreciate you both taking the time to help us with our decision!

IMO Dark Walnut would be my choice both the others will still alow the red to come through .