I'm thinking of making rough outlines of each shot using a camcorder before shooting with the Super 8 in an attempt to get things perfect and cut down on wasted film, but yeah you're probobly right, I'll certianly need extra rolls.
I am kinda in love with the Super 8 look and would be hard pressed to find a cheap 16mm camera (though it could possibly pay itself off due to film costs?)
I'm planning on experimenting quite a bit before starting work on the 30 minute film. I like the idea of some basic montages, quick videos practicing the Tarkovski-esque elements that I'll use later, or demos of planned shots just to get a hang of things, it's just going to be a bit pricy but I guess that's how it goes!