I haven't used Wet Coat for about 10 years, I had some go bad, it left a streaky finish that was a real PITA to fix. I don't know if it was a bad batch, or more likely a storage issue, I'd had it a year or so and where it was stored got to over 100f in summer. I do have 303 Touchless Sealant on the shelf currently, and I've never had an issue with it, but we've moved house and I have better storage now. I don't know if they've been tested back to back, but they seem comparable to me. I've also been able to get 303 TS at auto stores here for a while, Wet Coat had only online availability till very recently.
As for coverage, it does seem to get in places other stuff can't, it's almost like magic, I mean using high pressure water to make something coat and stick to a surface seems counterintuitive.
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