yay! It looks really good, and I know, proportions are hard for me as well.
maybe you could try using this as a guide (it helps me)...
http://3.bp.blogspot.com/-7bS-XNQmBnk/TeX7B0XqZMI/AAAAAAAAFTE/AWktwZT1XAA/s1600/Clipboard01.jpg
*please note that this is not mine