There's nothing wrong with using a stainless steel blade. One of my better shavers (best looker, too) and another reguler performer in my rotation are made of stainless steels. With that being said, the rest of my rotation is made of carbon, but I haven't noticed a difference in performance. They are a bit more difficult to hone, but they hold their edge longer.
Feather AC will give your customers the closest possible shave, but it may be a bit harsh. However, the base version is autoclave-safe.