some "official" TD Hs129 rpm recommendations ?

[LukeFF]

Originally Posted by EJGr.Ost_Caspar

Thats the very same only evidence of the ZFR, that we had (you know, we used your collection). Manuals might be somewhat misleading, as they were produced prior to the delivering of planes to the flight groups. So the reference about this installation is veeeery weak and was regarded as not (yet) worth the effort.

Yep, and to add to that, the only two known photos of an operational B-3 show it fitted with the standard B-2 gun sight.

Probably what happened is that the very, very first aircraft had the ZFR fitted, and the later ones used the standard B-2 sight. With only 25 planes produced and a service life of ~6 months, though, the true reality will probably never be known.