Vincent,
Thank you for your compliments. Although the craft appears small, they are actually about 4 and a half inches for the wing span, and just over 3 inches in length. Not huge by any standard, unless you're modelling in 1/144th!
Regarding the shade of blue, I have seen it as light as you've offered in your example, and yet I have also seen it as dark as in my usage. The following is a picture of a portion of the artwork on the inside cover of the Windsock Datafile for the Voison:

Since the actual painting of those planes, I have aquired numerous amounts of extra decal sheets from various manufacturers and find there is quite a variance in the offerings of the decals as well in regards to the shade of blue used.
In the case of the above pictured craft, all are fictional and are un-numbered or serialed and do not represent any one particular craft that once existed. They are intended to be generic and represent the type of craft for use as game pieces.
Thanks for your interest! I'm always trying to find details I can add to my models that won't suffer constant handling and don't add too many extra hours to my build times. I do need to expand my color palette and hope to find a shade of blue that will closely match what you have in your example. Perhaps for when I scratch build my 6 Morane-Saulnier 'L's.
John