thanks guys.
obviously theres no real way to no exactly waht youre putting ou without extensive testing; i was just looking to see how other base there cal burning. i would think its better to use the cyclocomputer as its based off of everything (heart rate, resitence via hr, speed, and cadence) and other methods will only use a certain number of those variables.
FWIW, i am going to use an average of the two highest reading i get, so roughly, 500 cal per hour for me during regular training.