Down here you can buy 6 blank cards in a pack, so I tend to just cut the six.
I sandwich the cards between some very cheap thin ply. I hold the cards and ply very tightly together, (needs to be tight to stop the card from moving), and hold the all together with sticky tape around the out side edges.
I can then attach the pattern to the top piece of ply.
I use a #2/0 Olsen reverse tooth blade.
When finished I attach the colored tape with double sided tape.
Hope this helps.
Marg