(Mods, not sure if this is the correct subforum, if not, please feel free to move it)
This was done in Germany where I am currently working.
I had picked them, because this was clearly the most serious place doing such applications, as it was the only one who said they needed to keep the car for up to 10 days for drying cycles.
This was not convienient to me as I lived 45 minutes away and so I needed a rental (which are fortunately cheap here).
Steps, that were done ( He sent me pics but it was via text not email and I have yet to move them to my email)
1 ) taking off the plastic and rubber trim pieces under the vehicle for access to metal surfaces they might otherwise cover.
2) cleaning the entire underside, drying. cleaning again
3) Spraying FluidFilm into all nooks and crannies into the cars body to include the hood, door bottoms and rear hatch. Spraying it on seams
4)spraying it into the box frame.
5) Painting the outside of the frame, suspension parts and many metal surfaces ( like the wheel wells under the rubber cladding and the underbody of the car) with Permafilm, a wax based protectant paint. It looks like a mostly transparent paint.
The entire bottom of the car is now covered in this. From laying under the car I cannot see any untreated steel (except brakes, exhaust/engine stuff like that)
6) Reattachment of rubber and plastic trim pieces.
7) drying
Interesting note.
The Gentleman told me he noticed that there was still a lot of consumer grade Fluid Film clinging to many surfaces on the underside, which he had to clean up, to ensure his wax based paint would stick.
This is interesting to me, because, it had been 16 months since that had been applied by me back in the US.
So it looks perhaps, the Consumer grade fluid film clings better than its reputation.
However, there were many places I knew I had sprayed that were completly bereft of my consumer grade FF application from Sep 2023 (when I had bought the vehicle new), so there is that.
Still I thought that tidbit was interesting.
PS: The guy also had a 30+ yr old MB, W124 300E in his shop.
Was told owner gets this done every 5-8 years. Car looks near new despite approx 30 years of age.