My son gave me a Gerber model 1055 folder with a serrated lower blade and a tanto point. While I have been sharpening traditionally bladed knives for nearly 50 years, this blade presents some new challenges as the point makes that radical turn that makes it a tanto. There seems tobe two separate edges that require sharpening. Are there some differences or special points I need to be aware of in order to sharpen and maintain the edge? Any advice would be appreciated.