Well, I've been messing about with this damn lump of balsa long enough. I've sawn it, filed it, sanded it, painted it with Tippex, stuck lumps to it, smeared it with filler and sanded and sanded and sanded.
So I sawed it in half:

and vacuum formed two windshields:


The front one hasn't come out well, the pilot's one is OK
There is a lovely Nieuport IV-G in the Flygvapen museum in Sweden. I emailed them and Torsten Nilsson, Director of museum collections unit took some photos for me. I'm very grateful that he has done this for me. Judging by some of the photos I suspect he quite enjoyed doing it
This is the windshield on the IV-G:

I think it shows a double skin to the windshield, the outside being flared and the inside a flat curve. So that's what i have done


The flat bit at the rear will get removed, it was convenient to stop the windshield spreading while I fitted the inner skin
Richard