Rit Dye Prep: After drilling, milling and stippling. First wash frame with dawn dish soap to remove any oils and or dirt, polymer dust etc. wear gloves afterwords as to not get any oils from your hands on the frame. Fill a large pot big enough to fit the frame length wise with water just enough to cover the frame while submerged. Heat water to boiling and add desired amount of Rit Dyemore I’ve found about ¼-⅓ bottle has worked best for me and stir well. You can mix colors to achieve a custom look. Reduce heat to a low-med simmer and wait for the water to settle a bit. I use tongs for doing my bath but you can also use wire or similar to lower the frame into the bath. You just want to make sure that if the frame touches the bottom of the pot it’s not there for long. If you are trying to color match another piece just have it sitting nearby and every 5-10 minutes pull your frame to compare colors. The longer the frame bathes the deeper the color will go. Once desired color is achieved immediately rinse frame under cold water to stop dyeing process. Then I use a soft brush and a little dawn again to remove any residuals. If dye is left on the frame it can and will cause uneven colors. Check nooks and crannies for build up. You can only dye frames darker you can’t dye them lighter. Sooo unicorn white, gray or fde yield the best results. It is possible to dye a black frame however you will just add slight pigment to the black ie; red and black = black Cherry. Whatever color frame you use will impart that pigment in with whatever color dye you are using. Fde+pink for example will yield a brighter more orange tinted pink Vs using a grey frame wich will yield more of a pepto bismol colored pink. The old color can show through if scratched deep enough. To do touch ups you can use some dye with a little hot water like a 3 to 1 mixture and just use a Q-tip or similar to brush the scratch. Then let dry and repeat till you have a good coating. I then like to use a blow dryer to bake the dye in and dry it. After a day I wil take a rag and wipe off the residuals. This method can also be used to achieve darker color tones for your stippled grip areas.
If your looking to achieve a two-tone look you can either tape off your areas with med- high stick frog tape wich will keep the dye away from where you don’t want it. Or you can use any clear coat non water based spray paint or sealer, tape off what you wanna dye and spray the rest. This will keep the dye from penetrating the polymer. Another option if looking to keep the original color in areas and your stippling is to dye just deep enough and then sand/grind down past the dye line to reveal the factory color and then stipple. You can also achieve some cool looks if you stipple after a dye job and then dip it again etc.
Before Rit dyeing
After initial stippling pattern and before polishing off the burnt high marks. It was my first stipple job and I overcame the learning curve quickly after this.

FrogTape 🐸 Medium or High adhesive. I've also used painters tape wich does not work well on stippled areas

Flex seal clear or any clear coat paint, cerakote or Gunkote etc.

After Rit dye bath using regular RitDye instead of DyeMore. Observe the bluish tones due to the separation of pigments in the powder. Use DyeMore!!! And lesson learned

P.s. I almost kept it like this but the color scheme was wrong for the theme and overall look I was going for. Kinda rad how the stippled areas matched the slide and the rest of the frame was a different color.
After RitDyeMore job and alternating random stipple, dye, polish repeat.

This is the effect achieved by stippling after dyeing. Dye, stipple, polish, rinse and repeat.
Another example of material that can be dyed, G10 knife handle scales.

Rit dyed Royal purple to match a build project.

I have an idea for a battleworn Rit dye finish. Wipe Vaseline all over the frame trying not to get it on any sharp edges or into any corners. Then giving it a bath, the ritdye should take longer to penetrate the vaselined areas making the nooks, cranny’s and corners a darker color than the rest of the frame.
That was a long write up. Appreciate it though gonna come in hand.
Yep, this pretty much nailed it! I use a air blower afterwards to dry off and get the liquids out of the nooks and crannies...
Thank you for the info, much appreciated!