Let's say I have square stock and want to trim away the outer edges until there is a cylinder remaining. I would use roughing waterline with "begin pocketing out of workpiece". The problem I have is that SC starts with an initial plunge that is really close to the edge of the workpiece. Sometimes, if my real life stock is a little bigger than what is in SC, the end mill will nick the edge of the piece on this initial plunge. I know I can set the workpiece to be bigger, but sometimes I don't want to do this, because it will cause SC to try to trim areas that don't need trimming.
The lead-in option doesn't seem to make any difference in this regard.