I finally finished a Scrin campaign run on verison 1.07. It turns out to be not worthy to run on this version since you don't start with Mastermind on Mission 3. However, I discovered a big time saver on Mission 1. If you save the game when the southern GDI MCV is unpacking and reload, GDI won't build any structures! This fact might make it necessary to time Scrin campaign runs by real time though.

Great find! This is very interesting. I haven't really messed anything with saving on specific points yet, but I definitely have to look more into that now. I wouldn't be surprised if you could use that in other missions as well.

IIRC, the only other mission where you see enemy MCV's entering the field is Nod Sarajevo. Your strat already takes care of the second part of that mission pretty well, but it's worth a try.

Yeah Sarajevo was what I had in mind. I tried to saving and loading multiple times and it doesn't seem to work. It also looks a bit different, because the buildings are all placed extremely fast and are probably not actually built by the MCVs, but idk how AI works exactly in this game. However I will try saving and reloading for other missions and see it it can be abused somewhere else.