I've done this job myself twice and now waxoyl falls into the same category as sandblasting. As Laninlandy said...
Pay for someone to do it .
He covered most of what you need to know.
Rent a steam cleaner to clean the chassis. You are teasing yourself trying to do it with a high pressure sprayer. I have a Karcher that pumps water out at something like 140psi and even that thing doesn't do as good a job as the cheapest steam cleaner.
Any dirt and grime left on the chassis will come back to haunt you.
You need to get the front wheels up on ramps when cleaning the front and then again the same for the back.
The chassis needs to dry thoroughly before you apply the Waxoyl.
Vanish doesn't remove Waxoyl stains from clothes.
Get hold of one of those paper suits that the spray painters wear.
Cover your skin to the best of your ability.
Wear glases or goggles.
It burns like hell when it gets into your eyes. If you do get it in your eyes, the only stuff that helps is milk followed by Optrex eye drops.
The best way to remove the stuff from your skin is Tetrosyl Gun Wash Thinners.
The first time I did it, I used a Schultz gun on a compressor and lost a lot of product into the air.
The second time, I used the Waxoyl spray thing that attaches to the waxoyl can. You can buy it from your local motor factors. That worked much better, was much more accurate and economical.
This time of year, you need a mate with a heat gun around keep the Waxoyl liquid. Time spent getting the can ready (and keeping it in tip condition while you are applying the stuff) will make things easier for you down the line.
Would I do it again? Not unless I really had to.
Would I recommend the product? Hell yes - look at my "Can Waxoyl last 30 years?" thread...