Its been quite a few years since I've taken Step 1, but I don't think it was quite as high as 20%. It was probably more like 10%. It was pretty easy though, the vast majority of it. Definately know your basic fryttte's principles, and the sympathetic distributions. There are going to be a few oddball OMM questions out there, like some crazy craniosacral stuff, but who cares about that... just guess the temporal bone and most of hte time you'll be right.
I cannot emphasize the importance of OMT Review by Savarese. It is the ONLY OMM book you'll need for the COMLEX, I promise you! You should just study it about 2 days before the big day, and that's IT!
Q, DO