Thank you Martin,

meanwhile I made some progress:
I found in my decals shoebox the HGW stitching, although thry are in 48th (they don't seem to make the 72nd scale version) I decided to give them a chance and tried (on the left) to stick a small piece of stitch on a spare plastic and "cover" it with a waste piece of the Aviattic lozenges, they fit together very well and I proceeded to use them on the plane belly.

Then I cut all the needed panels from the Aviattic sheet.

And these are the results:



I'm pretty satisfied with it...
Now I shall slide the crosses and the stencil decals over the lozenges, according to your experts' opinion should I seal the lozenges before sliding the other decals over them or is it possible to put the other decals over them and then seal all together ?
(I use a Humbrol acrylic satin varnish rattlecan to seal the whole)
Here is the leaflet with the stencils printed out on my Inkjet (see enlargement below to see the printer's resolution).


Ciao!
Antonio