Anyone have any opinions on this?

Also with the pulleys the length of the bore is about 29mm and it has two set screws. The shaft for the pulley on the end of the ball screw is only 15mm long. Should I be concerned that the shaft isn't long enough? Is tightening down the set screws onto the round shaft fine or should I grind down two flat areas on the shaft for the set screw to tighten onto?
thanks in advance