Enamel is oil-based paint; latex is water-based. Oil-based paints require turpentine or mineral spirits to clean up--much easier to just toss cheap foam brushes.

I have put up as many as five test samples on walls to get the right color. I learned to do that after painting a whole room and hating it--twice--which is when the paint store guy finally told me that a room will look like the next lighter color on the paint chip. Thanks, dude.

Give your new paint a week or two to see if you like it. Kind of like a new haircut--change always takes some getting used to. If it's still too much, you can always repaint. Caution--as soon as you get every room exactly perfect, the universe will make you move to a new house.