Great research, Csaba @pikofix
Agree with setting the goals prior to starting a build.
Trying to improve your skills is also what I like to achieve on each new build.
Looking forward to this airliner.

Details are the essence of modeling, my friend @pikofix!
And, yes, airliners do weather: for some reason, many 1/144 finished models that look shiny, look also toy-like...
Great selection of pics; excellent commenting on them!

Great photos Erik @airbum, thanks! I don´t want to make a very dirty plane, since it seems that the SAS Neos are quite clean. I have seen some of the usual pattern on the belly and those streaks at the windshield/door areas. Otherwise these are still very new planes, and barely used in the last one and a half years.

I am thinking about painting the vertical stabilizer and the winglets blue instead of using the large blue decals from LN decals. Zvezda provided the white lettering, but of course this provides the next challenge - what were the actual colors of the previous SAS livery?
The answer is easy, Google is our friend.

The actual blue color is Pantone 2738 C, a deep blue-magenta color, similar to the classic ultramarine blue pigment used by artists. Unfortunately no scale model paint manufacturer makes exactly this shade. Online sources and build instructions will give you very different recommendations, for example Tamiya XF-8, Tamiya XF-14, Revell 51, Revell 54. All of these are quite different blue colors. My plan is to refill my Tamiya and Vallejo range with a few basic colors anyway. I will try to find similar blues to the ultramarine shade, and then try to mix it myself based on those deep blue paints. If I can´t find the proper shade, I can still use the decals at the end.

The fuselage gray was Pantone 9083 C. The easiest way to get a proper shade is to buy XtraColor X338 SAS Grey (I got one of these for my abandoned A340 project). However, it can be tricky or expensive to buy this in the EU after Brexit, and of course here are also other options. One of them Revell 371, it is close enough to the actual color according to many modelers. Other popular option is Model Master Canadian Voodoo Gray plus Insignia White mixed at a ratio of around 2:3 (more white than gray) .

The engine red was Pantone 179 C. It is actually a tricky color, many modeler call it SAS orange, not red. It is indeed red by definition , but a very light one.
Again, the easiest option is Xtracolor X339 SAS Red (luckily I bought this one as well for that A340 project). It seems that there is no commonly recommended paint alternative to this. I would try to mix my own based on a light red color.

Thanks John @johnb, I have the gray and the red Xtrcolor paints. Blue must be mixed somehow, and I can use the common brands anyway. For me Brexit was a big change, because basically all of my online orders came from Hannants. I loved their selection of kits, decals, paints. Now ordering from the UK got too expensive and slow with the Danish custom process. Unfortunately the last local hobby shop closed recently after the death of the owner, and I had no other choice but change to the vey few local and German online shops instead.

On this week I got the paint masks as well. I decided to buy both KV and Montex, and give them a try. The price was bargain (3 euros per piece or so), let’s see how they work on the model.

3 attached images. Click to enlarge.

I looked a bit more into the details, especially of the engines. SAS has been using the CFM LEAP engines on its NEOs. Zvezda provided both engine options, so I have a set of PW1000G as well for trials if needed.
It would be very interesting to paint the fan blades realistically (dark grey blades with metallic grey leading edges), but that will require a set of custom masks. That is going to be a challenge, the diameter of the entire fan is around 13mm (ca. 1/2 inch for you with imperial units).
Another interesting feature of the engine is the inside of the intake. There are at least 4 colors, not 2 as the instructions show. I have to make a dry fit (or a test assembly with the PW engines) to verify my assumption, but I believe that I can actually assembly, fill, sand and paint the entire fan casing/intake before gluing the fan inside that part.
The last interesting part are the engine pylons. Those have at least 4 different metallic shades. Will be fiddly to mask it, but not impossible.
It would be great to paint all of these small details accurately.

LEAP engine photo Bene Riobó, CC BY-SA 4.0 , via Wikimedia Commons . I cropped the details from the original high resolution image.

3 attached images. Click to enlarge.

Are you sure about the black blades? - to me it looks like it is the reflection that does make them appear black? Will have to dig into that! Thanks for another great in-depth info though.

Yes, quite sure. The previous Iberia photo is indeed not giving the best view of the blades. The LEAP engines have a new carbon fibre blade design. This new design was one of the main contributors to the weight savings in the engines. The lighter blades also required lighter fan casing and other components.

If you scroll down on the CFM webpage below, you will see more details of the blades.

LEAP