Screw-in bleeds and such are not an absolute necessity for tuning those circuits. And may narrow your field of choice of carbs down too much. For instance, if it weren't for the screw-in bleeds, would you consider the Demon otherwise?

With a drill and tap, it is easy to thread most any carb for air bleeds. Or you can simply drill the orifices out if they need to be larger. And in most cases, the only ones that get adjusted are the idle air bleeds. Adjusting the fuel curve with the main air bleeds is not where most beginning tuners go.

For most beginning Holley tuners, the IFRs, IABs, PVCRs, main jets, and the Transition slot feed holes are the areas that give you the most improvement in driveability. (assuming this is a street car) And the T-slots and PVCRs rarely have screw-in jets anyway.

You may find that having a drill bit and tap or a selection of wire bits will let you pick a better choice of carb for your application rather than concentrating on looking for one that already has the screw-in bleeds.