what i did in the F-4N pack (and upcoming S pack) is a universal skin per aircraft year (ie TPS for F-4S_84). then inside each units skin folder i only have the decal, numberlist, and textureset inis. as said above different units get different skins based on when skin changed (ie VF-301_82, _84 etc). final part of the trick was that the decal folder was simply broken by year for unit markings and numbers for Modex and Buno (white, black, grey, shadowed etc) takes time to set up initially but allows a viable all users pack to be created and used. or even an all years for one specific unit. also for any special skins within an aircraft year (like the 75th anniversary schemes during the time of TPS) the special skin can still be dropped into the particular skin and all others will reference the universal