If multiple readers respond to a tweet you make, respond with both of their handles to get them to talk to each other. (wiseinkblog.com)
Until there is a downloadable comic in a format like PDF that can be used in multiple readers, you are really only leasing comics. (crisisoninfinitemidlives.com)
Haven't tested either personally but I have had multiple readers say they made them with quinoa flour successfully. (feastingonfruit.com)