Holley/Demon Carb stumble

So YR's got me thinking about ordering me some bleeds.
when looking for a kit???? like i would for a fuel jet kit.!?
Why can you only buy individual bleed size, But you have to buy 10 of them??????? The carb only hold 4 each right? idle bleeds 4, High speed bleeds 4......Right?

Next question, does .001 make a noticable difference or are they like main jet and you should make changes in two step at a time AKA 76 to a 74

Next question if i have the throttle blades open far enough that the idle mixture screws makes no difference i need a larger air bleed....Right.

next question, outer bleeds are idle and inner are booster/high speed bleeds....right?