First off, why are you limiting yourself to just WGU, although it's an outstanding brand. I live in the greater Chicagoland area, Elk Grove Village and would love to show you my techniques and products for doing RW & WW.
For me it's all about the tools, namely a great spray bottle and plush, edgeless mf towels. I always make up more product than I need because I pre-treat everything, whether it's a RW or WW, doesn't matter because not only do I want the product to break down the dirt but I want lubrication for the wash. Pre-treating not only helps break down the dirt but encapsulates the dirt and brings it to the surface to be wiped away...safely. You also need a good supply of plush, edgeless mf towels. A car the size of yours would probably need about 6-7 of them.
Once I pre-treat I wipe the towel across the panel, look at the dark line of dirt and roll that portion of the towel away and make another pass with the remaining clean section. I can usually get anywhere from 2-3 passes before I need to move to an entirely clean square, use all 8 squares! Once done I just throw that towel to the side and grab another one. This method applies to both RW & WW, even when doing a RW with towels sitting in the bucket soaking I pre-treat, doesn't matter, never work dry!
For tools I use the 1000 ml Kwazzer, Black Fire hand pump and airator sold through AMMO NYC for their Frothe WW, makes the job so much easier with quality tools.
In closing my go to for WW is N914 and for RW it's Griot's Garage Brillant Shine and CarPro Ech2o, I've even used the later for WW as well. For road trips or a change of pace I LOVE AMMO NYC Frothe WW, it's the only foaming WW, even more safe because of the foam cushion provided, I'd be willing to show and help you with all of this if your not too far away
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