Sinker...If you paint the boat yourself that's one thing. If you paint it for a paying customer and not done properly that's a whole different ball game. I have seen some very unfortunate people asking me to re-do paint jobs that they initially paid big bucks for. Like I said, I try to stay away from painting if I can and source them out to my contacts. I'm not saying not to paint. I'm trying to say be careful do your homework, ensure the shop is reputable and will warranty their work. We have done paint on boats where we have had to repair damage, which meant painting after the repair was done and then replace the decals such as Legend Boats. Yamaha PWC's which have that new light weight NanoexCell body is painted. When we repair the damage to the hull or sides, and we have done a lot lately( because no one else wants to touch them) we have to repaint them. Again, a very expensive job as we use a three part Yamaha OEM paint made by colorite out of the U.S. very durable and specific to ensure adherence to the plastic body and the abuse these wave runners get. We use the same vinyl flooring that Lund Boats use. Can be purchased from any Lund dealer. I'm sure there are others, however we have found it to be durable and nice to work with. A high premium outdoor floor adhesive should suffice however you mentioned aluminum plate flooring. I have never worked with aluminum floors, only wood and fiberglass. So that may be something you want to look into as far as vinyl to aluminum adhesion goes. I do not know anything about that. Wood would be much easier to work with, easier on the feet. Coated properly with fiberglass resin would give you those 20 years again and much cheaper? Also, if the transom is wood, coated and sealed properly, will give you years of no problems. few of pics of different floor and transom repairs may give DIY's some ideas.