Optishot - Changing the offset of your clubs

[golfallyear]

I have a set of Taylor Made clubs that are offset slightly. In Optishot, there is a setting where you can change the offset of your clubs.
Questions:
1. What does the number (for example .161 offset) really mean in terms length. The specs of my clubs that i found online is in millimeters, how does that relate to the number in Optishot.
2. Has anyone played around with it to see how much it effects the swing data?
3. Do you use these setting when using your Optishot.

Thanks for comments

[golfallyear]

So i just found out that if you calibrate your clubs you DO NOT need to adjust your club offset numbers. good to know

What about Offsets in the Club Sets?
If calibration data is available for a given club, it does NOT use the club offsets in the face angle calculations.