Those transfers you are looking at are all post war as the roundels are red/yellow.
If you're making a republican plane, all it should take for the basic scheme and markings is rudimentary masking skills. Just a green over blue scheme with a red stripe on each wing and between the cockpit and tail with the tri-color on the rudder. The hardest part would be finding letter number decals that are correct, but they are basic block letters and nothing fancy.