Make sure that the conditions (Airspeed, GS, Wind, Height) are always the same when you enter auto.
Sorry but I don't agree with this approach at all. You are up against Mother Nature and she controls you, not the other way.
The way I was taught is this : apart for obviously aiming (azimuth) for the spot, how do you avoid under/overshooting the spot ? Fly a base leg and turn in final when 100-150 ft AGL (assume you are not set up for a straight in). Get your airspeed correct, so increase your standard auto airspeed by half the headwind element if any. Moreover, it's all to do with the groundspeed as you approach the spot - do not use height AGL to judge the timing of the flare. When the groundspeed looks fast, that's when you initiate your flare.