Minwax wood hardener tends to darken and discolor the wood.
If you go by some of the methods shown on youtube where they heat the solution then put under a vacuum you are likely to cause a fire or explosion.
The fumes are stronger than sniffing airplane glue. The headache you get is from the brain cells that just died.
Minwax wood hardener was made to surface harden rotten wood so you can paint over it.
The point I am trying to make is that the minwax wood hardener method is both an ineffective and unsafe way to try to stabilize wood.
What I mentioned above is based on personal experience from when I did my own stabilizing. Wood hardener was one of the methods I tried repeatedly.
Those who do home stabilizing with cactus juice and other over the counter stabilizing solutions usually mix the dyes with the stabilizing solution. A lot of the times this method can end up with slightly muddy colors.
For really vivid colors the wood goes into a vat of solvent based die where it soaks until the dye has fully penetrated the piece of wood.
After that the pieces are dried and then stabilized. This process usually involves the wood being in the die vat for a period of weeks. But that is what it takes to get the really deep vivid coloring. I really like K&G for dying and stabilizing.
These photos show a batch how it looks when they come back from the stabilizers. Then what they looked like after they were cleaned up.