I just re-read your comment in my log and realized that you said you were starting next week... my mistake! Must be the caloric deficit that's causing me to have brain cramps LOL! Oh, and I hear you on the carbs... that will be my ongoing battle. I'm already looking forward to the week when I get to eat 50% carbs! I'll have NO PROBLEM with that week!
As far as the 1RM thing goes... my trainer suggested using a perceived exertion scale instead. If you feel like you're at like a 7 out of 10 by the end of the set, the weight is good. He just didn't think that finding the 1RM was necessary... I found his way to work for me quite well. Just a thought.