Shimano gives a torque spec of 50-70 in-lb. for attaching a set of shifters to the bars. I have a good torque wrench, but unfortunately there's no way to get a hex-bit socket onto the clamp screw -- it's way down in there and can only be reached by a typical L-shaped hex key.

So is there any way to judge the torque when hand tightening this fastener? I would guess that this is not all that critical and just has to be "tight enough not to slip", but was wondering if there's really any danger of stripping something or whatever. (I used to have a pretty good feel for stuff like this, but don't trust myself as much these days!)