Holley/Demon Carb stumble

I'm reading what your guys are saying and trying to exorb it.
I get the MAB's and think i get the idle bleeds (haven't messed with them but bought a idle air bleed kit as well). so will dabble into them in a while.

The thing i'm just not getting my head around is the holes in the metering block that you guys keep saying i should drill out and instal a .oxx this or that.
I will get it!
skrews i have a a #3310 vac sec 750 carb...But i guess i would need 2 of them to try them valve bodys.

cookietruck, that chart look confusing to me but i just don't have time to study it right now. Works craze)will be asking question when i get a minute to really check it out.