You gotta try vinegaroon. A gallon of distilled white vinegar. Two steel wool pads. Put them into something you can cover and be able to dip holster, belt, etc. Do not make airtight. Some gas is produced by the contents. Takes a week and a half to two weeks. I know, I know. But you will have a dye that dyes almost instantly and all the way through. You canot scratch it off. Submerge the piece of leather and when the bubbles stop and the leather sinks,you are done. Let leather dry normally. And the good part, it will not dye the hands. Might get dingy looking but it washes off easily.
You can dye some imagination into leather. The corners, the bottom, the top. Guaranteed a straight line .