what have you been studying biochem from so far? stick with that and use FA for a quick review, you can breeze through FA biochem section in one day, goodluck
The biochem shelf was the hardest shelf 1st yr and probably the hardest shelf out of the 1st 2 years - in dec 08 a 680/800 was 99th percentile. All my shelfs 2nd year you had to score close to 800 to get that high
During 1st year I was not worried about the boards so I knew little of FA. The test was a while ago for me but I don't think FA is enough. I remember them asking some pretty obscure stuff.
I would use BRS or Rapid Review and then do a question bank - I did RR Biochem and it was good prep, it was difficult tho