not really, the width and heigh of the frame are driven far more by the size of
a standard sheet of plywood than anything else.
The steeper the angle to the chain on one side, the lower the tension to the
motor on the other side, which hurts accuracy (due to chain sag and the
possibility of friction being high enough to prevent the sled from moving as
desired)
but there wasn’t a whole lot of thought put into the exact details, just getting
the motors far enough out and up to work.