[FlaminSarge]

Leo: Exactly. Using m_iTeamNum to swap a player to a team tends to break certain damage sources (e.g. flamethrowers) since the player retains their vulnerability from their old team. So if you swap a player from spec to RED they remain immune to flamethrowers. Since I swap a player from RED to BLU, they retain their 'RED' characteristics even while on BLU, and so I can use ChangeClientTeam to properly swap the spectator to RED while they're on BLU. When the BLU players get changed back to RED, they already had their RED characteristics since it was an m_iTeamNum swap, and so nothing breaks.

Below is the plugin to change visible max players for MvM, using the convar "mvm_visiblemaxplayers". Don't set it above 10, but set it at -1 to use the default visiblemaxplayers (as in, the plugin will do nothing). This convar defaults to -1, so you'll have to set it to 10 in server configs. It WILL spam your console with warnings about 6-player stuff and can potentially cause a bit of lag (since it has to set the visible max players every time TF2 sets it back to 6).
The plugin doesn't take effect outside of MvM.
I haven't tested this plugin yet, so let me know if I botched it.

Originally Posted by dr4ggy Just wanted to say that if the server is on linux you can filter out the mvm_visiblemaxplayers console spam with grep: ./srcds_run <params> | grep -v Setting\ sv_visiblemaxplayers\ to\ 6\ for\ MvM

I'm taking his word for it on this one, I don't have a linux server to test on.