I think it would be difficult, at best, to get consistent results. Tons of places for smoke to get caught in a design leading to more smoke discoloration. Not to mention the more obvious risks of fire.
Page 3 of the manual specifically advises one to not do this.
The most I would probably do on this is cut and set up a jig to do two of them side by side, depending upon the size of the cardstock and how the design falls. You could do two 8.5 x 11” sheets of cardstock if you rotate the design 90 degrees counterclockwise and point the longside of the cardstock towards the back of the machine.
That doesn’t minimize time like stacking material would, but it decreases the overall set up time