Forget the overdraw. They are all but obsolete. They were used in the day of heavy aluminum arrows so one could shoot lighter and faster arrows. With the lite aluminum and carbon arrows of today there is no need to use an overdraw. Your razortec is plenty fast with out the over draw. A two inch over draw is only going to take off 16 - 20 grains so why put up with the hassles of an over draw? If you want to shoot faster just buy lighter arrows. Actually, I doubt you could put one on any of the TEC bows.

Yes they are detrimental to accuracy. Think about it and you will see that the farther back the rest is from the bows pivot point (the grip) the more the rest will move the arrow side to side as it is moving across the rest should you torque the bow or move it in any way before the arrow passes the rest.

Grab a pencil at the tip and with two fingers and wiggle it around. How much does the opposite end of the pencil move compared to where your fingers are (pivot point)? The same thing happens when you move your rest farther away from the bows pivot point and the farther you move it the worse it gets.