There is nothing wrong with using #7 followed with #20; I have done this for many, many years without a single problem.
As I said before, the cleaners in the #20 are more for assisting it to bond to the surface rather than clean it like a cleaner wax. Sure the very mild cleaners in the #20 may remove some of the
#7 but certainly not enough to lose the benefits of it.
Here is a post from Mike Phillips (Meguiar's) from his own website that discusses this very issue: Can you layer #20 over #7
Quote:
"#20 does contain some light chemical cleaners; but they are only a small percentage of the total volume of product. Percentage wise, it’s nothing like a true cleaner/wax like our #6 Cleaner/wax in the Professional line, or the “Meguiar’s� cleaner wax in the Consumer line.
The chemical cleaners are used in the formula to help clean the paint so that the polymers can better bond to the surface. This allows the wax to last longer and protect better.
While serious enthusiasts will tend to use a “dedicated paint cleaner� and or clay before waxing, the average consumer likes to do one-step. By including some lite cleaning ability, Meguiar’s insures the wax will properly bond, and thus last and the result is a happy customer.
You can certainly apply it over #7 and #3.
Does it remove these polishing oils? Probably not enough for the human eye to ever notice.
I like #20, it works great, lasts a long time and it's easy to apply and super easy to wipe off. It’s an awesome wax for finishes in good to excellent condition.
It's highly water and detergent resistant, which makes it a great wax for climates that get a lot of rain, like Oregon and Washington.
Always shake this product up very well before use.
Two thin coats are better than one thick coat.
Allow the wax to completely dry before removing, usually no longer than 15 minutes.
Hope this helps...
Mike"
End of Quote (from
www.theartofpolishingpaint.com and
www.showcargarage.com)
So, if I were you, I would use #7, then #20 and topped with #26!!
Cheers!
Tim