The only product out there that will make a difference when applying by hand is meguiars scratch x. Just be sure that you're feeling pretty healthy that day cause your arms and body will go numb from all the effort it will require. As far as durability factor collinite is some pretty serious stuff but you may want to look into a synthetic sealant. Megs M21 is pretty good stuff and it will definately outlast any Nuba out there. You could even look into getting Opti seal which is also another synthetic sealant. Or if you wanna spend a little bit of money there's always Zaino but I feel it's way overpriced and they're alot of products that do a better job for less money. I would just go cruise around on
www.autotopia.org and check out some of the product reviews. That should point you in what direction you wanna go.