I've read a few reviews of Opti-seal on here, but mostly descriptions after first using it. Folks seem to like how easy it is to apply and the looks afterwards, but I haven't seen a report about how it lasts. I'm anxious to try it. Should it be applied below or above a carnauba or does it even matter? This seems like the perfect product to use as a booster after a few washes following a full correction detail. Any comments on how folks like it after its initial use?
You can apply it either above or below. I usually apply it above a nuba. Actually, you don't need to apply anything over or under it, as it's a LSP already, but I do just because it gives that "extra" shine. Yes it's very easy to apply and you only need a small amount of it to do an entire car. I wouldn't really consider this one as a "booster" because it's much more than that. Like I said, it's an LSP sealant and you'll usually get about 4+ months out of it. I guess you could use it as a booster, but it would be a bit of overkill. If you're looking for a booster I'd try Dodo Red Mist. I love it and people have compared it to Z8. It also can be used as a LSP, but the durability is much less (about 1 month) than Opti-Seal or even OQD would be OK, though OQD does not offer and protection as far as I know.
Clever Nickname has summed it up great. Optimum Instant Detailer and OCW are perfect to go over OS after an ONR wash