So I went and checked out the material (and its changed to Davids Emproium... lol) and omg theres so many types... how do I know whats too stretchy, and whats not stretchy enough??

Also they had some material that kind of felt ok, and was super cheap at $1 a metre... but it was this awful dirty olive green colour (which would explain why its so cheap, its a nasty colour!) would it be worth getting enough of that material to have a go at making a Moby in case I F it up, and that way havent wasted so much $ on it? Or is it so easy to make that botching it is virtually impossible?
Oh and in the pattern, the centre part looks diamond shaped, but on videos on youtube, the front panel is more of a rectangular shape... does it matter either way?