I am making the shoes stilt-style, high heels with the heel cut off.
I'm confused. Are they stilts? or heel-less shoes? you said both. Did you actually mean platform shoes? (for reference) http://www.hairstylesandfashion.net/...s-for-women-3/
I would not build from scratch completely. At the very least I'd rework a pair of heels that you like the way your foot sits in them, then remove the heel, add platform, etc. Not supporting your arch can really do a lot of damage to your feet. Also, practice walking in them well ahead of con day.