That's all well and good Karnak, but it does nothing about ships that we want in there showing up 20 years early.
Are you trying to prevent time warping or make exceptions? First case is already taken cared off, as stated above by judicious usage of SPECIAL class, and second case is what?
Two different animals that require two distinctly different approaches.
Also, when you mess with the SPECIAL_ROLE field then you are messing with the shipyards. Sometimes, you want a ship to be available in the shipyards, but not as AI in the missions. That means you use SPECIAL class, but not SPECIAL_ROLE 'R' and the ship cost is whatever is set for SPECIAL class in the economy settings.
You want a ship in 20 years early? Just don't use SPECIAL class and change the YFA date.
I think the I-CCZ should be HEAVY_BATTLECRUISER class and YFA -20. That's 40 years earlier than it's original YFA.
I guess that I need to do a dyna campaign to show how it all can work. I've yet to see an admin. use the dyna tools available to its fullest potential. I prefer to wait until the SQL server kit is fixed though.