Leather will need a lot of care and a specialized stitching machine. My MIL does custom interiors and has all of the specialty tools and sewers and she does a beautiful job. Her personal choice is that she don't do leather. She can do leather but mainly she works with vinyl and fabrics. She has done quite a few rods and custom and she prefers working on the customs which normally don't use leather. She was always a good seamtress so moving to cars was fairly easy, just took time, patience, and practice.

If you have a done similar work in the past and don't mind loosing money in mistakes, than go for it. If money is any issue, go to a pro. Get several bids on what you want. There is a lot of variance in pricing on interior work. Good luck with it if you decide to keep in in house.