The problem is that you have competing goals:
1) want the cog to not unthread itself when riding
2) want the cog to come off easily when wrenching

The solution is to use the correct technology (a fixed hub with a reverse-threaded lockring.) If you're going to cheat on that solution, then don't expect good results, choose either safe to ride and hard to remove, or suicidal but easy to wrench on. I'd go with the red AND a bb ring.