When I had your exact setup at 20 - 30 degrees, I was running the stock pilot and 280 mains in the winter. Needle clip in the center position, and air screw 1 1/2 turns out. I would drop the mains to 270 in the spring and fall and run 260's in the summer. Ran great for me and I was at about 900 - 1100 ft also.