Okay got some early rules up. Any advice as to how to condense them into postcard-sized form would be appreciated! Also sure there will be some comprehension issues so do please pick them apart.
Viewing post in Postcards from Rivoli jam comments
About the size of the text block/ rules. One trick is a different font (some maybe legible even with a different size than the one used right now).
Second trick from my digital layout days is to change the numbers of column - do three columns look fine? (This may lead to a third consideration).
Last, would it be possible to rearrange the contents on Your page? For example, arranging counters on the long edge of the postcard. Not easy, I know, but it is also a way to squeeze as much space as it is possible.
Hope this helps or at least does not give You too much trouble!