I have a big angus that I used for many years. Bought it for the same reason (6'4") Great bag. the only reason I got rid of it was that I found the large foot box would get really cold. If I moved my feet I would have to warm it up again. Being I am a restless sleeper I was always moving, so I always had cold feet!
I may not be the best person for a temp gauge though. Like I said before, I seem to always be cold. It has not been until I moved to the two down bags I mentioned above that I have actually been warm at night in a sleeping bag!