Many thanks for all comments.
I'm fairly happy of this build, even if there are here and there a number of small faults.
I don't know when I will do an other NMF but, with this one, one lesson I surely learned: don't always trust people in model shops.
For the painting of the model I used Alclad II products: various shades of metal lacquers and, as a base coat, "Gloss Black Base".
In my experience, the latter is a very good base but absolutely not what the seller told me: a primer.
The adhesion to bare plastic is good but cracks, scratches etc. aren't highlighted like with any normal primer and I discovered them only after the first metal paint was applied.
Therefore the need to sand, polish and repaint some areas.
By the way I also learned how helpful can be metallic waxes like those shown here:
Stamperia
The work perfectly to cover any defect on metal surfaces.
Alberto