Just passed the SCWCD. My preparation included about a month's reading HFSJ, SCWCD 1.4 notes from Mikalai Zaikin and Exam Cram 2 by Trotier(Old one). Couple of weeks back my score on HFSJ mock exam was 56%. Make sure you are thorough with this book. Few of the questions were outside the content of HFSJ, so you might need to go through the specs.
I thought the exam was pretty challenging. I took almost the whole 3 hours to finish it. I had to make few educated guesses and I wasn't too confident. But I'm glad in the end I'm through.
Just drill HFSJ into your head and you should be through.