I used these guys.
https://www.seatdoctors.com They can get you almost any color or make you the color if you give them something to go by. They have an amazing FAQ and instructions on what to do here
https://www.seatdoctors.com/frequently-asked-questions. They are also pretty responsive for any questions.
Prep is key! You want to use a water based cleaner to scrub the leather with a sponge to get all of the contaminants out of the leather. Then I used their crack filler to fill in the cracks in the seat and if you need to lightly sand the excess off you use 800 grit sandpaper I believe or maybe 600. The grit number is on the bottle.
After you clean it really well and let it dry, you then want to clean it with isopropyl alcohol. Once dry, you can start applying the dye. Make sure to shake well so the paint blends together as some of it might settle. Then I poured a little dye into a plastic cup and used a paint sponge to dab the paint into the leather, don't brush it in. What you see is after 3 coats.
Make sure you wait sufficient time between each coat so the dye drys or else if you apply a new coat it will bring up the old coat if it didn't dry properly. I waited about 30-45 minutes between coats but when I asked them they said the longer the better and you can even wait over night. You can always apply more later too. I didn't use a heat gun or a blow dryer but I think some people do. It will depend on the temperature and humidity based on where you live.
After the final coat, wait at least 48 hours and buff the seats with a lightly damp cloth. During this process I saw very little dye come off of the seats onto the cotton cloth so so far its holding up well. Haven't put them back into the truck yet as Im waiting to hear back from them on the topcoat.
There is also a top coat you can put on as well to further protect it. Im waiting on them to confirm the process to do it as I don't want to mess anything up.
As for how it's holding up, so far so good, they say on their website that once you do this it is permanent so it shouldn't come off on your clothes as it is now "in" the leather.
Also, one more thing, they do say it is not easy and maybe even not recommended to go from black to another color as it may not come out right unless you do something like red. But going from black to a lighter color is difficult. In my case I was lucky as I was going from tan to burgundy.