I'm a newbie but did use the search function before dyeing the skin. Skin was whipsnake with white background and black patterns. I used a deglazer and dyed from both sides. I pegged it on cardboard and let it dry overnight. Came out flat and still quite supple.
The dried dye came out the color I wanted but was bleeding off even after quite bit of buffing. Running a damp cloth over it was still giving a lot of bleed off. This is short piece I'm using as a test. I ran cold water over it until it came clear and repegged it to the cardboard. As it dried this time, it pulled out the tacks and curled. The color had shifted lighter but not too far off.
Some more use of the search function turned up suggestions to use neatsfoot oil, let dry, then mop n glo, and buff, then use a clear shoe polish at the end. I did see that the neatsfoot oil would darken the color. As the color was a bit lighter than I'd hoped for after the last drying. The neatsfoot did make it more supple again but came out darker than I wanted for my main project. I can still use this shorter piece elsewhere. But a few spots on the sides where the belly scales had been--skin had been descaled, had not gotten as much dye, As that is near the edge and uneven, I'd planned on trimming that off. But those lighter colored bits came out closer to the color I wanted and the neatsfoot added a depth or glow that is lovely. I may try for that with dyeing another test bit with diluted dye lighter than what I want and hoping neatsfoot will take it near my target and add that depth.
However, would glycerin have been a good alternate choice with less color changing effect? It would be easier to get the color I want and not have to guesstimate. But there is one more problem that may be a factor long term on this project. It's going on the rim of a drum and I want to put a durable sealer on top of the leather. If glycerin pulls water back in and then I seal the top and glue it to the wood, could it rot since it won't get any air exchange? I could glue it to a fabric backing with some porosity or another thin leather. That might be a better choice as I could use velcro to make it removable.
Any suggestions?