Hi,ad an ITALIAN and model maker who built 4models of the SM79 i can tell you that tuo are doing an excellent job.
All the companies that built the SM79 had their own personal painting scheme for the internal structures,using anti corrosion green,or the anti corrosion grey,or a combination of the 2 colours,green for the cockpit and gray for the rest.
I personally hawe always chosen this the last option.
I remember that the anti corrosion green was produced in 3 different shades : pale green ( very similar to the english Sky green) the shade you used,and the grass green of the Officine Reggiane Caproni whorkshops,which i remember, thogether whit Ambrosini and SIAI were the companies that they built the SM 79 .
Good continuation of the built