My first piece of advice - you're going to have to try a few times before you're happy.

Second piece of advice - try using monokote instead. I'm not downing Ultracote - but it's such a lower heat covering, and it seems to shrink up waaaay more than Monokote - also I have trouble with Ultra cote where there isn't much overlap between pieces - I end up shrinking until the overlap is gone - it's like the UC doesn't like sticking to itself very well.