I am probably going to be crucified here but here goes,
In my experience, mass produced Yosh cams are not that accurate. They are often slightly out and do not make much gain.
I personally believe that you should have a set of cams done by a reputable engine man. Made for your bike, they can produce excellent results.
I would like to hear frank adams response to this as I would expect he would be have good knowledge on this topic.