The important thing....
What matters IS NOT the overall size of the texture... but the size of the mapped areas IN IT!!! The overall size matters in terms of what the particular sim accepts to render... HOWEVER... the MAPPED areas within it have to conform to the mapped model areas for painting... What you need to do is resize the mapped area of the Armada Argentina texture to fit the size of the normal mapped area that came with the textures of the model... (original livery) Obviously... you need to be able to: 1. Work with layers, 2. Have a paint program like Photoshop, latter PSP, or similar where you can resize textures without losing detail... [and the required skill to do so] (best color resolution to work with should be 8 bit color... 16 is not so good)...
Resizing the overall area of the texture just increases or decreases the size of the MISFIT... no magic there... In other words, you take the original texture that works as a pattern... next you superimpose the Armada Argentina texture over it...
in a layer atop it.. and resize the Armada Argentina texture UNTIL IT FITS EXACTLY OVER THE BASE ONE... WITHOUT LOSING DETAIL (otherwise, you get a fuzzy texture without detail)... Then eliminate or just flatten to one layer...
The final resolution sometimes has to be adjusted to only 256 colors.. because FS 9 FOR SOME MISTERIOUS REASON.. does not accept repainted textures that were high-res in the same resolution in the originals... repainted... and then reinstated on he model... In other words... the now beautiful repaint.. does not show in the sim... just a textureless grey model... that surprised me the first time.. and I discovered that put into 256 colors it worked... OR... saving the repaint as an EXTENDED Bmp..
with Alpha, etc. did the trick too... the problem with extended bmp files is that they deteriorate with successive opening to add or subtract details, etc. It ends up with those dreaded "moiré" patterns... But there is a solution to that... YOU DO A MASTER IN HIGH DEF... Photoshop or PSP layered file... and every time you re-edit the file... 1. you open the master... 2. re-do it... and 3. Save the new file as an extended BMP on the model... a bit tedious BUT NO LOSS OF FIDELITY....
Hope this is of help... if you want some tutoring on this.. let me know...
Cheers,
G.