I am building a Dornier Do 335 with an 81" wing span and I am concerned about how much power I am going to need to get this thing off the ground in relation to the altitude at which I live.

The plans call for a front motor up to .90 and a rear motor between .90 to .60 which seems very reasonable until I begin to think about the fact that I live at 6100' above sea level. I am thinking that I will fit a 1.20 in the front and a .90 in the rear to compensate for the loss in power.

Anyone have any experince with high altitude that can tell me if I am over reacting here or I am thinking correctly that the addition size will help overcome the loss in power I will be dealing with?

Higher elevation thinner air.. 120 & 90 sounds about right.