Holy cow! That’s a fine looking S2T!
I seldom visit the P3D forum, but I fell like I was missing a lot of lovely addons.
I can give a little help with XML coding for the retardant system, especially if you wish it to interface with FireFighterX (I have just finished doing the same with Milton Shupe’s French TurboFirecat).
Keep us updated about how the project is coming along!