...and this is where things start to get messy and complicated. Using my little "halfway point" trick was great when working with rough, basic shapes, but with so much more detail added there are three times as many major points to reference when trying to determine the correct positions for them at the halfway point in between. Considering the way that they overlap, I wouldn't recommend actually doing this unless you really need the visible physical reference--though plotting this out at first does help to identify the key points that you need to match, and I'll leave it visible on most of my screenshots just to help follow where the points should meet.
Really, though, you should get used to just "eyeballing" the halfway points in between. While treating your animations like a geometric graph helps with accuracy, you can be just as accurate if you learn to develop your eye for estimating in-betweens--and the more you practice without guidelines, the better you'll be.
