To give a bit of history, I've had been playing a TM Burner 7W and SQ2 5H from the beginning of 2011 to May of this year and then switched to a Superfast 1.0 5-18 fairway and 4-21 hybrid, and Superfast 2.0 6-27 hybrid. I hit these pretty well but occasionally would hit a high fade.
I acquired a 910F 19* fairway early in August (traded the Superfast 1.0 clubs). First game out I used the D3 setting and hit pretty well. Eventually settled on B3 after extensive hitting at the driving range (what was happening was D3 would work well on the tee and B3 worked better off the deck). Played for about a month at the B3 setting. Last golf game I was developing a low pull. Took it to the range last week and re set it to A1 and was hitting dead straight.
Acquired a 910H 27* mid Aug. Set it to B3 based on the fairway wood and it was doing pretty well for 2 golf games. A month ago I changed the setting to C3 beause I was missing the green about a foot left. Took it out to the park this PM and found it pretty effortless to hit it dead straight with the A1 setting.
Got a 910H 21* as a birthday present this weekend and A1 is the perfect setting.
One thing that happened during the time frame is that the lie angle on a set of Eye 2 irons gradually went from green dot (2.25* upright) to yellow dot (1.5* upright) and finally blue dot (.75* upright) when I switched to AP1s in May. I have the AP1s set -1/4" (which matches shaft length of Eye 2s) and 1/2* upright for the 6 and 7 irons and 1* upright for the 8 iron thru LW. My iron play has gotten progressively better.
The other change was I shortened my driver from 45" to 44.5" in May. Prior to that, I generally drove straight with an occasional high fade and now I stay pretty much in the center of the fairway.
My theory is I had been hitting upright with an outside-in swing path on the driver and fairways since 2008 (I used to pull it before and that went away after changing) and now I am taking a less upright stance with a more of an inside-out path. I was also using a slightly closed stance on the driver and fairway wood before. Now my stance is pretty square.