I used MindManager to produce the signs I need for a recent Open Space event on an A3 Canon iX5000 printer. This proved to be a very effective way to do it. MindManager by default fills the printed page. Simple signs can be made using the Central Topic for the text and using the line and background colour to produce signs like the meeting location names.
Note each of these signs is the same width but because of the number of letters the width height ratio changes. Padding out with spaces or changing the topic margins can help.
Slightly more iconic signs can be produced using the image library. For instance the one Law of Open Space is you can use your feet.
For the Four Principles of Open Space I used a music festival as an analogy. 120,000 turned up for this one, it always finishes dead on time (they want to use the same field next year), queuing early is good – you start meeting people and the comic folk singer brings along an opera singer. The audience switched from mass morris dancing to Nessun Dorma. Photos mine, event courtesy of Fairport Convention. Here I placed the images in floating topics and arrayed them around the central topic.
But next time I will make them separate central topics and print them each on their own sheet of paper. They were too small on a big wall.
Or I could use the poster printing function in the print menu to produce a 10 foot banner like this one. Which is just an image and text in central topic with no shape.
You can see what happened at the event in maps, video and photographs at Open Minded Day 01.
I hope this give you some ideas for your events. Any questions, please ask.