You don't need to cover all the back with tape... just a few strips is sufficient.
When you tape it to a board of scrapwood you can fix this board to your tabel and hammer a few small nails just outside your G10-plate.. Together wit the tape it will not move for sure..
If you figure out the right sequence you mill the parts and where the vectors start, you will have no problem at all. Your parts come out clean and fast..

Kees