Sig LT .40 with OS .40fx
Hi Joe,
You probably should find a way to get a .46. I am flying an LT-40 with a Magnum .46 near Fort Collins and on a hot day (high density altitude) the climb performance is okay, but not great.
I think on cool days the .40 would be okay, but you might be happier with the extra power in the end.
Good luck. I'm really enjoying my airplane so far.