I have used a product containing Dupont Krytox for many years.This is what GM recommended for the door, roof and hatch seals on Corvettes and other cars. The only problem was it was $30 a tube. Members of a Corvette Forum discovered that Leslie's Pool Supplies sells it as Pool & Spa Lube. It used to be $5. a 3.5 oz tube, it is now about $8. Still worth it, works well.
Before all the fancy and expensive coatings were available, plain old glycerine found at any pharmacy (behind counter) kept rubber pliable and squeak free. It's used for compounding medications. Best part it's dirt cheap.
I've read that 303 is the best, and I got some. It sure makes any black platic or rubber parts look great, and it is supposed to have superior protection.
But, how are you all applying it to things like rubber seals. Spraying seems pretty messy.
I use one of the round pads that I use to apply wax with. I just spray it on part of it... and rub it on. I use it on everything rubber or plastic. I even spray/wipe it all over the freedom tops... because of the sun protection.