help: (Finger Bit for Oma Antarex) thread

we first rough cut our sink cutouts by coring the corners and (http://maplered.com) using a turbo blade for the straights. then we use a magnum w/ a top bearing electroplated drum on a template (SLOW). from this thread it seems clear that a finger bit is much better. what is it made out of? does it chip out really bad? is there an attachment for the magnum for the template guide? please give me the dope on the right way to do it.
thanks,
Mike