Hi Brett,
This cook started about 9:00 pm and finished around 4:00 pm
Only had one brisket in it, which takes longer then a fully loaded one.
Also mine is one of the first ones with a 750 watt heating element, the new ones are 1,000 watt.
Here are a couple of links on high altitude cooking
http://www.pa.msu.edu/sciencet/ask_st/081893.html
http://extension.usu.edu/files/publications/publication/pub__5790807.pdf
Thank you,
Brian