I am thinking about replacing the foam light seals on the film backs of my RB67. I have several questions abiut this. A) There is a company (www.micro-tools.com) that sells several foam kits. Which should I get for this project? There were several sizes and thicknesses ,some self adhesive. B) How do I remove the old gummy seals? Do I use a solvent? If so, which type and how? C) Should I scrap the idea and send it off to a pro?