Hello, I have a new MSR Whisperlite stove. I'm planning an overnight this year in Yosemite. Altitude where I will be using it is around 7000. Has anyone determinded how much fuel this stove uses each time you heat up some water? The reason is I wish to caculate exactly how much fuel to pour into my bottle and reduce weight to just what I'll need. At this time I'm only planning on two times, dinner and breakfast. Thank you.