SuperVillian- Welcome to Autopia. Heh heh, I'm the last person to worry about longs posts
Sounds like you have some great cars in your family! Since you're happy with how they look I dunno about making any big changes to what you're doing. Let's see....
1) Somebody's gonna flame you for using dish soap, but it won't be me. I gather this is an infrequent thing that you only do before major details.
2) Nothing wrong with Mother's clay. I wash while claying and thus avoid having to do extra washes. If you use enough clay lube (or wash solution as lube) you shouldn't have to wash any "clay residue"/etc. off anyhow. FWIW I found the GC shampoo to lack sufficient lubricity to avoid wash-induced marring, but many others here love the stuff.
3) #7 is sorta labor-intensive and doesn't really do what it's designed to do too well on basecoat/clear paint. If you like
Meg's stuff of this type I'd try the #3 (yeah, it's OK by hand) or the #81 instead next time you're buying.
At this point I'll add my $0.02 on polishing. I don't think I've *ever* seen an unpolished car that didn't have *some* marring (my catch-all term for "swirls", "cobwebs", scratches, etc.) that could be improved by using a mildly abrasive polish. I keep my S8 as close to marring free as I can imagine, and I still have to polish it every few years. Even if there isn't any marring, using a *very* mild polish won't thin the clear or anything like that, but it will clean/prep/shine the paint even better than the dish soap/clay/#7 routine. Something like 1Z's Metallic Polish (MP),
Sonus Paintwork Cleanser, or a similar product just might amaze you. Worth checking out.
4) If you like how
NXT and KSG work for you there's no reason to change. Since you use the KSG, maybe some regular cleaning with
Klasse All In One would be a good idea before/instead of the #7.
5) If you like the #26 (which makes sense, especially on black), no reason to change.
Souveran can, however, look incredible on black vehicles (hint hint).
Other stuff: I don't think there's much you can do about the stone nicks. Once paint gets chipped you can either touch it up, have it repainted, or (my usual choice) live with it the way you are now. When I had a C5 I didn't worry about stuff like that, but I did use mildly abrasive polishes on it with no problems. Putting a "clear bra" on it before it gets chipped/nicked is about all you can to do avoid this sort of thing if you really use the car in the real world. I remember a museum curator's words of wisdom: "Real cars have stone chips".
I wouldn't use that Sears polisher. I'd rather do things by hand while saving up for a PC/Cyclo. If you do use it, only use the foam pads and only use it to apply, not remove, product. The terry pads/bonnets can scratch many paints.