Is not very clear to me what you would like to achieve with this mod and in which way this should be an improvement? It seems to me a very complicated way to add a new FM.
In your download you are also adding a folder with a very old ntrkwizard to create and/or modify FM taken from the FreeModding site while we have improved tools for the same end here https://www.sas1946.com/main/index.php/topic,42832.0.html
Dear Frankiek!
1) I didn’t take this from the Freemodding website, because I simply didn’t look at anything like that there.
2) The original DiFF itself, which I slightly modified, was downloaded via ftp upload from a “virtual” disk, the site aviaskins.com
3) The mod was posted to help people like me, who make mods on their knees and are not a professional modder and do not know how to make their own class files.
By the way, thanks for the link to Freemodding, I’ll download it and take a look!