Years ago I wrote a MogProg program for Moggy which edited and re-named 3dz and TPC skin files so that a skin for slot A could now be used in slot B.
It has recently been updated so that it can make a 1.40 version of files in an older skin folder. It can also do the reverse.
Ray's original SPAW45 Sea Fury was in the Hurri slot, apart from one file which referenced a Spit 14 TPC from another SPAW45 aircraft. No problems if both skins are loaded, but a blocky prop in cockpit view if only the Sea Fury is loaded.
So I tested the 140 version all by itself in the root folder. Every plane used the skin because of the 140 naming system, but there was no blocky prop.
So I "MogProgged" the 140 Sea Fury files back to the Hurri slot. It works faultlessly all by itself

Nice.

That blocky prop was a left over from something I tried with SPAW.

I like the inside and outside prop that Col. Gibbon came up with a long time back so I tried to make it universal in SPAW. Unfortunately I came smack dab into conflict with the slotted texture files so after you noticed it in the first online version I converted all the props back to their original configuration.

If we had the 1.4 PLANE***.3dz system plus the extended tra file it would have worked because each folder could have the same props.