Should sled dogs be kept inside at nights, and how many dogs on a team?

I have a new dog sled and i am wondering if i got 4-8 siberian huskies does that breed require being kept inside or outside at night? With that many dogs how is it possible to keep them all in the house. I live on a farm would they be better off outside all of the time in their heated dog house (10ft by 10ft) with furnace and dog beds and can leave or go in anytime. Also how many sled dogs are used for the average sled team? I will be using them sometimes for standard transportation is 4 huskies enough to pull 5-10 Miles per day and how many mph would it run, or would i require 6 or 8. Thanks. Dustin