I started cutting portraits about 17 years ago and I always cut the hardest parts first, eyes, mouth. I have never glued my patterns directly to the ply or wood I have always used blue tape but I am always extra careful when taking it off, the I sand with a rotary sander, never had a problem.
Now after saying all that, I started doing a portrait yesterday and I cut the hardest parts first, a necklace and the eyes, feeling please with myself I packed up for the day. Went out there today and keep in mind this is a fairly simple pattern now the hard bit are cut, I broke the mouth and it didn't matter which way I looked it was not fixable. I will start again tomorrow and get it right.
Marg