That's rotor shaders you used for semi transparancy. Additive shader is more for different illumination including night/day possibility. Furthermore additive shader would be dependency on a vehicle to load it without error.

That's weird, I thought that you'll need to have additive shader to toggle that glass part to be semi transparent.

Works perfectly, thank you very much. Btw. I can see both pilots even without additive shader.

Ok I see, Thanks for the tip. It is now 4 dogs and 12 crews

It just can be changed by modtools, not the editor itself.
It's VehicleID section (close to bottom), where you can edit count of men and dogs (for disaster).
Efficiency is how fast they clear the building.

I have no idea what you are talking about. There is one term called efficiency, but I honestly don't know what it is doing. It does is set as 3 times compare to the vanilla setting.

No I mean the crew is still the same? I think two men and one dog. You may edit the values, because would make more sense to have a bigger rescue crew on board.

I set the door at the rear cargo bay door

Did you leave spawing crew and dog count as it is set on vanilla helicopter (next to values)?