Cling-a-ling Mount cushion
Cling-a-ling stamp mounting cushion is the best to use with unmounted stamp sets. It comes as an A4 sheet and has a self adhesive side which you attach your stamps to, and a 'cling' side which attaches to an acrylic block. You will need a piece of cushion for each stamp as you attach it permanently to the back of the rubber.
You will need 1 sheet of Cling-a-ling to mount 2 Illusionary Artists stamp sets, which are A5.
After years of mounting stamps, I can tell you that this is simply the best mount cushion there is!