As long as it fits and functions in your weapon I wouldn't sweat the "z" too much.

Unless you using very high dollar measuring tools it is completely plausible that you could get .001-.005 JUST because of a lack of close tolerances within the tool. Add to that the same because of less than top dollar match bullets . . and you have what is referred to as "tolerance stacking" whose net result is significantly more than any one piece of your stuff alone.

I'd be singing a different tune if you were loading at or near max loads, or match ammo. But you say that you are not so . . . .

Oh, before I forget . . to specifically answer your question, .001-.003 on average from the Dillons, .0000-.0002 on the single stages.