Thanks! Here is a quickie little diagram for how I made the ruffle out of the sleeve. The trick is cutting it into a spiral because the inside edge of the spiral is shorter than the outside and it makes a ruffle without gathering.
I pin my tees on my body inside out. I have a duct tape dummy form, but it's old and doesn't look like me any more. For simple stuff like this, pinning on my bod is just easier.