With a beam type wrench the position of your grip does have an effect. This is why they have handles that are mounted on a pivot. You are supposed to apply your force with the handle acting through the pivot (in other words, without the handle "bottomed out" one way or the other) so that the line of action of the force is in a precisely known position.

I have not read all the links (it's getting too late tonight), but my strong opinion is that a beam type torque wrench is more accurate than a click type. It does not require calibration as long as it has not been physically damaged or used beyond its rated capacity. It is a less convenient tool than a click type, but it is accurate because of its elegant simplicity.

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1987 W201 190D