i made sure to be as current and as proficient as i could be prior to getting to training. On my interview i was current, had only been a CFII for a few months, and i continued to do instrument instruction and lots of time in the sim all the way to my class date.

As far as i'm concerned, it really did aid me going through training to have all the instrument rules fresh in my head, and to have developed a heck of an instrument scan prior to seeing the little box of a simulator. good luck.