The least aggressive way would be to use 2 layers of tape and reset the bevel completely so see what you could get, or you could try to even the spine out if it's not too uneven. I would try 2 layers of tape before trying to go to more drastic measures. If it gets sharp and shaves well, then he'll just have to stick with two layers, but the size of the bevel is more cosmetic and can be overlooked as long as it will hone and shave. Just my $.02