First I used the Hvac-calc from this site.

I have some questions about set up and size.
I came up with 50983 BTU. So a carrier 58MVC60 should be good. Right?
Set up and adjustments, things to ask installer.
1: Oriifice size is set 0-2000ft from factory. I am at 2350ft, should it be changed?
2: Set gas rate input. Basicly how is this done?
3:Fire and set BTU input to match design rating. Basicly how is this done?
4: Set airflow (temp Rise) Done by measuring air in and out of furnace after 10min, speed up or slow down blower until proper temp reached. Right?
5: Does he need to check and adjust gas pressure coming into house?

Other than a neat and tidy job is their anything else I should ask?

Thank You