I don't know if you were hunching your shoulders and turtling more in #3, but to my eye, that looked the best (at least as far your upper body). back relatively flat, good arm angle, etc.

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Chicago Cubs - 2016 WORLD SERIES Champions!!!!

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Thanks yeah part of that is due to I lowered my saddle but I also lowered the front quite a bit with the spacer removal. I must be relaxing my back and shoulders more in #3. There is a certain amount of variability in how a person can flatten or arch their back while in aero position. I'll have to practice on the trainer and watch in the mirror to see which position I can hold comfortably the longest. Thanks for the comments.