I had another go at doing some one-sheet cards... and this time I took my time about it and ruled up a guide sheet on a piece of blank cardstock so that it can be reproduced at leisure! Last time I got ten cards from my one sheet - this time I managed fourteen, and there are two tiny strips of paper left over that I didn't find a use for.
Here is my template, hopefully large enough for you to read the measurements. (Click on the image to see a full-sized version.)
And here are my fourteen cards. I kept them very simple and let the paper be the star... they're just embellished enough to finish them off neatly. It was a sheet of 'back to school' paper so I made it into general 'hello' and 'just a note' cards that the Heroes can hopefully use any time.