Sig LT .40 with OS .40fx
Joe,
I was flying my LT-40 with the Magnum .46 today (about 80 degrees F) and really it flew with plenty of power to spare. I asked around the last couple of days and apparently a lot of guys do fly the LT-40 with a .40 engine.
So, do what you think is best. The 40 would probably provide adequate, if not overwhelming, performance.