If considering an M70 style safety on a DG rifle, I would go for a 2 position and not a 3 position. It's either on or off. No inbetween.

And IMO, it should lock the bolt down when on safe, so that when you suddenly end up needing to push off the safety in a hurry, you don't get caught with the bolt handle having been pushed a bit up by some bush, which would prohibit you from taking off the safety.

I have this on my M98 Mag. in 375H&H, and am very pleased with this set up.

Or, if not scoped, and if you are used to using them, the old original M98 flag safety.

The most important IMO is that you practice with it so much that you don't need to think about it when operating the safety.

Erik