Re: Self-Taught Iaido
Hmm - have to agree that the chances of you going wrong are very high without good teaching.
Having said that, if you were to try things on your own, then my advice is to use a live blade. A live sword is a dangerous thing - and you will have to treat it with respect. It will also challenge your tanden and spirit. If you want to avoid losing parts of your anatomy you need to go real slow and careful. There is an element that the sword itself can teach you - if you let it.
Even with that advice, I would seek out a teacher to get basically started - you might only need a few lessons though to to give you stuff to work on. Then work, work, work the basics - don't worry about advanced/complicated kata.
Note that this advice is based on my experience learning Kashima Shinryu battojutsu (rather than iado).