Here's what our concrete floors looked like before (please pardon our unfinished baseboards and demo dust and debris):
Our concrete guy, Jeremy, showed up bright and early Monday morning, and proceeded to mount protective plastic on the walls before applying a few stain options to the floor for us to review. The first round was somewhat shocking. We asked for a light grayish stain with a hint of green, but the first round looked basically like black to me (the row at the top). We asked to see a "toned down" option, and the two colors on the bottom row were applied to the floor. Both of these still seemed too dark, so we all agreed a good polishing with the lightest hint of green stain and several coats of polish would do.
↓ Grinding the floors