You only need the mat to cover the blades, not the whole die. I use a small mat on a big die all the time. The strip die is the only one that has to have the right size mat to work. When my big strip die mat gets cracked I cut it to fit other die shapes. I have also used old rotary cutting mats cut to fit. I don't baby the Go, I try all kinds of stuff with it. It's about 6 years old and still works like new.