I have been searching the net and here are a couple of finds so far.

As far as three stage Mod 70 type and having used a Mod 70 for 30 years the safety is either on or off as the mid "safe" position is bypassed in one fluid motion,theres no stopping or extra clicking when that big stag gets up in front of you.

http://www.brownells.com/.aspx/pid=6759/Product/M_98_MODEL_70_STYLE_SHROUD_WITH_WING_SAFETY

http://www272.pair.com/stevewag/turk/turklosafe.html