We tend to want about NONE but that is kinda unrealistic with a chain set.
They all slack a hair' after some run time, but you really don't want timing to bounce around , like most of us. Unfortunately once you settle the rpms it will move around a hair. Tensioners can be a good idea, but not full proof.
Think Gear drive.
If that chain is allowing the cam to go back and forth now , New, then its not getting any better after some run time. Did you line hone to the point of needing the shorter cloyes chain set or did Howard's mess up...?
I run a mancini chain set ,billet, its tight...even after refresh...but it still let's that time mark move just a hair when rpm settles...