You can use Honda studs or metric 6/1 bolts . Same thread as the bolts I sent you to mount your intake down with . Ace Hardware has a nice selection to choose from .
Just FYI I was pretty easily able to mount an Urban reed cage to an nc50 case with very little dremel work to open up the case a little wider . Urban/hobbit reeds will be your best bet to make your nc50 screem .