You could look at hobby or full size cam lobes for a rule of thumb. Obviously you are trying to achieve a certain lift and duration at manageable accelerations.
I posted some info about calculating acceleration from lift, duration; base, nose and flank radius at http://www.cnczone.com/forums/showpo...48&postcount=9 (Cam Grinder)
What acceleration is OK? Consider the inertia and strength of the parts. Also, achieving low jerk, as in smoothly changing acceleration is important, not just low peak acceleration.
from the thread at http://www.cnczone.com/forums/showth...948#post362948
NC Cams has a lot of wisdom to offer on the subject of home made cams in many threads. Just read past him not seeing why a hobbyist would want to learn to make cams.