How can I increase alien numbers on the battlescape?

So, if I want to (say) make 8 aliens spawn on a light scout mission, how would I do that?

I feel really dumb for having to ask - I feel like the answer is right under my nose, but I can't seem to find it in the .xmls in the assets folder. I did check the mods sticky thread at the top, but zzz1010's "double crew" mod doesn't seem to be hosted anymore, so I can't peek at what he changed.

The files in the Ufocontents folder I think.

Thanks for the fast reply!

I just checked it too, and yep, is is the files in that folder.