I'm at about 900ft elevation and I would probably try a 45 pilot and one or two smaller on the main. Try a 152 and if it runs better try a 145. If it starts to cackle or pop a little in 5th or 6th full throttle, then you are too lean. Don't run it too long like that, jet up one size at a time until it pulls hard and clean. You want to find where it just starts to run lean, and then come up one size on the jet for the best performance. On the needle, when you say bottom notch, do you mean that you have them dropped lean with the clip towards the blunt end or raised rich with the clip towards the pointy end? If you have them raised rich all the way up, you definitely want to drop them leaner for better throttle response and power at part throttle.