1/ How to get around the problem of always centering the cut in plywood:
I make a mark on the panel, corresponding to the middle (vertical to home position), and another on the bottom of my frame.
This one was made a little wider, so that my wooden panel can slide on it. So I can cut objects on the edges with the same precision as in the center. I just have to measure the distance between the home position and my second cut, on the software (I use Illustrator) and then postpone it on the bottom of the panel. Then I slide the panel until this new mark aligns with the other at the bottom.
2/How to cut a small piece of wood without having to create a large frame around it:
William, my colleague at Tous aux abris! (a mad inventor dressed in a yellow jacket), came up with pieces that look like mickey heads, which he made out of nylon with his 3D printer. They have the same thickness as the wood panels we used for batboxes. To engrave small pieces of wood, which are already cut, we frame them with 3 cleats, and we are moving these pieces around. The sled slides on them because they are rounded. See below the links to movies of a bat surrounded by random mickeys…
tousauxabris.org/docs/cutting_bat_logo.m4v
tousauxabris.org/docs/random_mickeys.mp4