Xbox 360 Halo 3 and Reach co-op

I’ve completed the Halo 3 campaign on legendary and I’m currently working through Reach on heroic.
Would anybody be interested in co-oping both of those campaigns with me on legendary? 2 players is acceptable, but 4 players would be ideal. I’d really like to get the “Annual” Vidmaster Challenge if possible.
Add or message me if you’re interested.
I’d be willing to try some custom games if I get enough people.

I’d be willing to help out with the campaigns, assuming this is still a thing.

Not too sure on the Vidmaster Challenge thing tho.