Is it the Sonüs Ultra Fine clay you spot clay with?
Yes,
BUT....the latest batch is different from what I`d received previously and I`m decidedly displeased with this new version. The older, green, stuff was *MUCH* more to my liking and I doubt I`ll buy more of this new gray version. Simply different stuff and I don`t really like it.
And is it cause you spot clay so often as you see/feel contaminants you think that is why you don`t get contaminants build up in the longrun?
That might help a little, but I`m really just focused on not having nasty-looking (if minute) specks of stuff on there and I want any ferrous contamination off before it turns into rust-blooms. (Yeah, clay is imperfect for that but usually works OK for me.)
Hehe that question got a bit long LOL.
Not as long as my answer
I don`t question what you are telling about your experience. I`m honestly interested with your regimen to maintain your vehicals. And I have the Sonüs Ultra Fine clay at home but not got to use it yet. I am a bit lazy and throw chemicals on the paint instead LOL. And the draw back is that I don`t get the full longevity of the LSP I use. But the Gyeon Wet Coat that I have used this winter is so easy to use. And get me a couple of months longevity with no extra topper....
Heh heh, hey...*DO* question anything that seems weird/wrong/questionable/etc.! I`ve come to realize that my experiences aren`t necessarily the norm and if I can help anybody get more with less I`d love to.
If your Sonus SFX is the gray stuff, I`ll be interested to hear how you like it. Had I not had the previous green stuff I`d probably like it OK but now I`m spoiled. I do find that their clay(s) work best with their Glyde lube.
Ixnay on that "throw chemicals"

Do things...everything...right and life works out better IME. But anyhow..ya know, I`ve never had my LSPs fail prematurely due to insufficient prep, and I hardly ever do anything for prep at all! I`ll just be washing for ages and then decide to throw (uh-oh, now *I* am throwing chemicals on the paint!) and still get the incredible durability here that some probably find hard to believe.
On my wife`s car, for the last..uhm..gee, almost three years now..I`ve just been using either OCW or IUDJ as a Drying Aid with no "real"/conventional LSP. No problems with it at all, so what you`re doing with the Wet Coat sounds sensible to me.
These days I`m all about keeping our vehicles in *my* version of OK condition with as little work as possible. To my pleasant surprise, it`s going well...and my version of "OK" sets the bar *awfully* high.