I haven't viewed Mac's as a prime resource, several of you have obviously been disappointed with them at times. I recently purchased a partially restored car the had the Cartouche interior kit in boxes but no sign of the installation instructions. I sent an email to Mac's asking if I could get a copy and offering to pay for them. The next day, I got an email from Jim Monczynski with the instructions attached and an offer to answer questions if I had any as I completed the install.
OK, that didn't cost Mac's any more than a few minutes of Jim's time but the prompt reply was gracious and more than I expected. Good Job by Jim.
I just put a Cartouche upholstery kit in my 1915 touring car. My advise is to check fit before stapling (or tacking). I started the rear seat first and attached the upholstery at the bottom because that is where the wood was and the instructions said to start there. It was a little tight at the top. I should have put another board in a little higher and started there. For the front seat I did just that and it worked out better. I also remove some cotton at the bottom so the seat spring would fit better.
I added cotton at a lot of places to fill out the pleats where they were a little flat. They made a special kit with 1913 style upholstery for a 1915 car. I made some leather fittings for the irons and for the wear places. I soaked the leather to stretch it where needed.
There are some good Youtube video's showing the installation.