You're getting some nice, even dye jobs there. I like to use Fiebings or Lincoln dyes that can be thinned with alcohol. I then spray the piece with alcohol first so the dye takes more evenly. I also have never heard of using hot water. I've heard of people using plain water but not hot water. The whole idea is to slow down the dye from soaking in too fast and getting darker spots in the finish.
The exception to that is if I want to get a patchy finish, then I don't use alcohol first and dab it on with a cotton dauber getting it as textured as I want.