bodymedia and BMR questions

brianparow

I just started wearing a BodyMedia Link and was wondering if I could semi-accurately calculate my BMR by wearing it for 8 hours sleeping and then times the calories burned by 3 to get a good base?
Then is it optimal to eat right around that many "NET" calories for optimal weight loss without losing muscle mass?

I am also eating high protein and no wasted calories, 6 meals a day, at least 10 cups of water and 30 minutes cardio/20 minutes light weights...