At the end I used Humbrol ClearFix that I had at home. The white effect from the reflex (don't know exactly how to describe it) it's hardly noticeable.
So I'm back with this model, after many tries I've been able to shape the new air intake/conduct the easiest way by printing a drawing in scale and using it to measure. I was discarding this solution as all the found drawings were different and from picture was almost impossible to identify correctly the shape. However it looked that was the only alternative to move on.
I sprayed the top window transparent green and again the helo drab, still need to paint doors and doghouse in red.
Masking did not work as expected, more for the surfacer than for the paint, however i may have still some chance to recover, let's see tonight. Worst than this was only the imprecise scribing.
I will complete the model anyhow, even if I consider it ruined, as will serve for training and looks decent if you don't look at it closely.
The picture says it all.
View attachment 71957
Bye for now,
Francesco