I've become addicted to this tute! I have made a few for myself and friends. Can't wait for 3/4 sleeve cheap T-shirts to show up in stores again, since I do prefer slightly longer sleeves. Quick tip: I usually wear 18/20 tops (snug) or 22/24 (loose, sometimes just right). I started making mine with size 30/32 tops, and they were large enough to share with my BFF, who wears size 28. So, there's a lot of flexibility in size ranges, but it's probably safe to use a size just one up from your usual. The length seems to be the real determining factor, since you want at least 6 inches to cut off from the bottom. HTH!
Great job! But you needn't have gone to all the trouble of rigging out the dress form--you could have just used me for a body double. I feel your pain on plus-sized busts. I never come *close* to filling them.