I removed the vinyl lettering on the Midnite Sun, which has an Awlgrip
painted hull, just this last fall. I tried all the various solutions which claimed they would remove lettering/bumper stickers/ etc., along with plastic razor blades to protect the paint
/hull....none of it worked. They all sucked.
The only solution I found satisfactory was the heat gun. Use it on the lowest setting and keep it moving so as not to create any hotspots or damage the hull in any way. Do one or two letters at a time. Then use a plastic putty spreader with a beveled edge, that you get from any hardware store, to get under the edge of the sticker. If you get it right after heat application, and you peel slowly and very gently/smoothly, the lettering should peel right off. If it rips, use the putty spreader to get the small bits off.
After removing the lettering use a citrus based cleaner to remove the residual glue. The non-petroleum based stuff they sell in the auto parts store for removing tar from auto bodies works well.
My lettering had been on the boat at least 15 years and came off no problem using the above method.