Yes, I'm sure the barrier is right under the MF regardless of the applicator thickness--of course what you guys are saying about the thinner applicator getting into tight spaces makes sense--I still have my head in the old-school coating days. I used to follow Anthony Orosco's advice from the original Opti-Coat days (Anthony had his own detail shop and was the founder of the Optimum Forum, you know him today as the importer of NextZen).
Opti-Coat (or for me, Opti-Coat 2.0, the retail version) used to come with a yellow foam applicator. Anthony thought this absorbed (and wasted) too much product, so he stuck the applicator into a nitrile glove, and wrapped Scott blue shop towel around it, and used that to apply the coating. So I would just use the blue towel by itself in those tight spots.
I guess maybe that makes Anthony kind of the grandfather of the suede-microfiber-wrapped-around-a-foam-block method, or even these saver applicators. As I've mentioned here before, Anthony, by his telling, is also the conceptual father of WOWA sealants. The story he tells is that he and Dr. G were demo'ing Optimum polishes at a GM plant in Texas, and went out to dinner after and Dr. G asked him what kind of new detailing products he would like to see (this was about 20 years ago) and Anthony said "I'd like a sealant that you can just wipe on and walk away, and it will last forever", so Dr. G went to work and ultimately came up with Opti-Coat, and Opti-Seal along the way.
