Optimum has a number of installers who specialize in headlights (a lucrative market given now many yellowed lens I see and how expensive replacements are) - several provide their own warranties. One successful installer in Hawaii ( a tough UV locale) offers a 2 year warranty and has had no problems. FYI
all Optimum Coatings gain depth and shine as they cure - 48 hours after application the look should improve. I believe you can apply Hyper Seal over Opti-Seal (Optimum has not tested) but agree there is minimal change in shine...overkill.
if you polish the scratch you will be removing the Coating - installers will do spot repairs and there should be no effect on the warranty if the original detailer does it. You could polish yourself and apply Gloss-Coat but that would negate your warranty.
funny to see Dann listed as "new to the Forum" - while not active on the OPT Forum, Dann is anything but new to Optimum. A past pro installer, Regional Manager, and current VP of Business Development, Dann is as knowledgeable as anyone could hope for and a welcome voice here!