Gimmie few I'm not on my regular computer. May I suggest organizing the parts by size in folders for 1,2,3 and 5 m engines/ tanks, each folder having 3 sub folders, one for tanks one for engines and one for adapters/ decouplers the parts that don't fit in those catogorys would be in a folder titled Misc. Anything that wouldn't fit in the above folders would go here.one more thing: the proper rescale factor to get the PAM to 2.5 m would be 2.5? I think it would look better wider: pic of IUS second stage motor a Orbus 6E: