Pretty cool design! For tintmasks check the tennogen guides, it explains the process of tintmasks pretty good and you can do tintmask in substance painter easily , they also provide a painter's tintmask shader which is a bit old but can work if you know substance painter pretty well.
About the Tennogen Tool , tried to export twice with different items types but it still save the tintmasks texture name as "FilenameTintMask_d" in the "TennoGenExport.zip" files. So, did we have to change the name manually in the zip file? I have also checked if there is any new updates of the tool on Steam but it shows no new update. currently it is Build id 5586380.