Try the attached plugin. Only allows admins that are able to Kick players to spectate T's otherwise only CT's can be spectated.
If the round is
not running it will allow anyone to spectate anyone.
No Commands or CVars.
Keep in mind that if you open the Spectator GUI it will still list T's because that list is build on the client side.
Attached SMX File is compiled with Sourcemod 1.11.
Installation:
DHooks is
required or you could use SourceMod
1.11.6820 or higher.
Put
cssctspec.smx into
addons/sourcemod/plugins
Put
cssctspec.games.txt into
addons/sourcemod/gamedata
Get Plugin will fail because of the DHooks requirement