I would sharpen it however you feel comfortable to be honest, just like any other knife. What i've found IMO is that is sharpens up very easily and holds an edge quite well. If you follow the factory bevel with the fine, x-fine, and xx fine dmts then strop you should be able to get your edge VERY sharp. Your ceramic rods should do fine maintaining the edge, as will stropping. If you want, you could even go a little coarser and thin the bevel a few degrees, I wouldn't go any less than 15 though with a chopper, murphys law and all.
As I said, it's common place for Busse knives to ship with fairly obtuse edges, which isn't a sign of poor quality, but rather them knowing that some people are going to get one, and start smacking concrete with it for no reason. A little thinning and some polishing, and you'll have yourself one of the best knives on the planet.