Dear Simon,
Your book really seems to becoming quite interesting...and your new approaches surely will be read with pleasure by some of us.
De Zeng's site do give information to which Flugplatz or aerodromes did have ZZ Lorenz Instrument (IFR) approach aids, so it can be of assistance >
https://www.ww2.dk/lwairfields.html
I understand that the searchlights were only useful for directional purposes (some kind of an aid to Navigation) if the weather was good enough (a certain amount of ceiling and without too much dense clouds)...Flying inside a heavy thunderstorm (or 10/10 and full IMC), I doubt you will ever see it (particularly if you have electrical statistic, bolts, etc.; "the full of it")! And, of course, the searchlight is not an Instrument Approach Aid, for a "blind" (nowadays called IFR) approach and visual landing at "minimums".
Maybe some real experts on LW Flugplatz can tell us, if the searchlight we are talking about was a special device (60cm, 110cm or more) installed in the middle of the runways (I have never seen such a picture); for Navigational Aid (and purposes); or if we are talking of one of the searchlights of the field defences (Flak Abteilung) that COULD be switched, by an order from the Gefechsstand, to help pilots when the weather required it....Personally I would like to have read or translated a German (LW) order, informing which were the "Weather Minimums" to have the searchlights switched-ON...I have never read about that.
I also have never seen or read about the ZZ Lorenz instrument approach...It seems this was some kind of rather primitive ILS (Instrument Landing System) used nowadays for IFR approaches....However nowadays you do have, at each aerodrome, a pattern to be flown....How was it like in WW2 and foreign aerodromes? It was to "each individual pilot to make his own individual Instrument (IFR) approach" or there was some kind of Landing Chart available (I doubt and have never seen such)?
Basically, each pilot was trained to use the ZZ Lorenz and in moving from aerodrome to aerodrome, he had to familiarize himself with the obtstacles and surroundings, to not hit them whilst on an Instrument Approach in bad weather. This is, at least, what I guess was the "standard procedure" at the time...
Maybe someone else can add further or enhance us....
Keep going...it is becoming quite thrilling for us which are following the process of this book from outside...The results and full manuscript surely will be astonishing to read...
Adriano