Your first assessment is correct. I really wanted to get it in there the first year but just didn’t plan it well.
1. Because I have the gun and a gallon of fluid film sitting here, I will likely try that first. If it flows well and sprays nice, and the pb blastershield is available bulk, I may hit the more exposed areas with blaster through the gun. However the hoses on the fluid film official gun will not fit in the small holes around the truck in the doors etc, and I’m currently unwilling to add any more holes. Ymmv. I will use cans of the blaster shield in the smallest holes. I purchased the graffiti adapters as well as two spray nozzles with small tubes attached to adapt both types of fluids. One was plastic and one brass. The plastic will work better in the warm weather and the brass in the cold weather with the cans. You can coat the whole truck with adapters for less than the cost of the gun... it would take many gallons and lots of time saved to change that equation. Cans are as fast as you can spray and move them.
View attachment 3097906View attachment 3097907View attachment 3097908View attachment 3097909For which product goes where, the fluid film creeps and mostly looks dry after getting the dirt film (needed) and the blaster still looks dripping wet. Blaster smells less but both are very similar. Fluid film is available in black, as are others but not blaster. I’ve seen the blaster described as fluid film and Vaseline mixed together.
2. I sprayed every metal object, and did not worry about any rubbers that contact oil as a part of their job. Make sure you do not spray areas with cosmetic or porous rubber. Those are the ones that can swell. I sprayed and sprayed

obviously not on confessors, belts, rotors, etc, but everywhere safe in my head.
3. With the small adapter tube for the cans, I could reach every inch of the vehicle. Frame was coated inside out and front to back as that was a primary goal. Thanks again for sharing this information. So basically spray using the gun where ever possible, and then use the cans and graffiti adapters for hard-to-reach areas like inside the frame.