So interp is a personal preference thing much like huds. There are some interp settings that are objectively better than others depending on your pc and connection or could be another factor I'm not familiar or informed with.
cl_cmdrate / cl_updaterate: should usually always be at 66 for a stable packets to the server. You can go to 100 if you wish but that's recommend if you have a god tier connection.
cl_interp_ratio: should be either 1 or 2 (I recommend 1 for projectiles and 2 for hitscan) on the rare occasion 3 for unforeseen consequences
cl_interp: If you put this to 0 that will make it go to the lowest possible interp which can cause some registration issues when you are in a battle. So for projectile 0.01515151 / hitscan 0.0303030303
cl_smooth: Should always be 1
cl_smoothtime: should either be 0.01 (or 0.015)
It's just dependent on what you are capable of handling for your system and game.
If you are wondering my opinion on what you could use I'll put.