I use the sfg-2 and I have not found any accuracy problems like you describe, except to say that when mine was behaving this way, it showed me that the spring was binding on my rb-300. I would say that if it isn't floating in the same spot every time, that there is friction (or resistance) somewhere. Evan with my immedia arm which has a lot of damping, mine always ends up in the same spot, it just does it ssloowwww. And since I have this arm, naturally I have to use it often. I always give it a soft careful tap just to be sure.
As far as extra wear on the stylas, I am not qualified to say, but I prefer to use it with the sound on, so I can 'hear' the friction. What I think I hear is that there is a big difference between a stylas running across a dirty groove with some speed and sitting on metal with hardly any velocity.
Here is one more thing to consider; TWL makes the point to be careful not to hook the stylas. I think that it is important to use the gauge perpendicular to the arm so as the stylas flexes as pressure is applied, it can slide in the groove rather than push against it.
