Dave,
I have had one sprayer "clog" on me and that was because I didn't use the product for a week (trying a different product) the problem I have had is the sprayer nozzle leaking after a few...
If allowed to dry on the tire and not cleaned off then not dressed sure it will cause dry rot but I would assume (reading how meticulous you are) that you wouldn't allow that to happen...
Wheels: Full strength (Generally on the wheels that I can't use Megs Wheel Bright on)
Tires: Full strength
Wheel Wells: Full strength
Engine Bay: Full strength...
This is somewhat true... Yeah if you are going to the cops with a "suspicion" of them being a dealer... Otherwise I don't think a druggie is going to come after me especially if I did it on the DL......
Honestly on the B-Pillars I would sand them down a bit (you could even use some green Scotch Brite) then shoot them with Dupli-Color Trim Black paint... I love that stuff for restoring faded trim......
I'm Chris the owner of CrownKote... If you would like to stop by the shop sometime I would be more than happy to look over your cars and give you some ideas...