Need to know a good choke size to get good drive ability...my car pops and snaps at part throttle..she wants to be wide open all the time,I need her to drive nice at low speeds. I know it's not just the chokes that need two be changed.
If any one has a good combo... jets,chokes,and so forth I would like to hear it Thanks.I have 30 mm now

For an A12 engine, making peak power at 6000 RPM, use 30mm chokes. Richen up the acclerator pump if it pops when you open the throttle.

what motor, what cam, what revs, what comp, twins, single...
your asking how long is string....

You have three areas that the jetting covers: idle, progression and full throttle.

The chokes determine where in the rev range that full power happens, the smaller the choke the lower in the revs, too large and you lose response down low.

I would be disconnecting the accel pumps to check the idle and progression as it sounds like the top end is OK. With the pumps disconnected you can make sure that the accell isn't covering for a weak idle/progression mixture.
Once warmed up, very slowly try to accelerate through the rev range, without the accel pumps you will quickly find any weak spots in your idle and progression circuits. I repeat VERY SLOWLY or you will flat spot straight away due to the lack of accell pumps. As you move up through the rev range you will need to richen up the flat spots and lean the fluffy areas.

Once you can very slowly rev it cleanly through the entire rev range, reconnect the accel pumps and it should be pretty close..

What controls the snapping and popping?
Car runs great ..just not in cruise mode.The pumps?
some one told me that was lean pop and to richen it a little at a time till it goes away???

For steady cruising, it is the main jet + air corrector jet. Use a smaller air corrector or a larger main jet.

But if you are using the stock size jets for 30mm chokes it should be OK. Steady cruise air/fuel ratio is good from 14.7 to 12:1 and will not cause popping -- for nearly all engines except those with high overlap camshafts.

More likely is caused by a vacuum leak... unless someone changed the jets previously.

Main jet is 115mm and Air corrector is 200mm .
These are new carbs I never touched them yet.
And I forgot to mention I bought 28mm chokes.Haven't got them yet.
I think I need to use a 165-180 air corrector jets and Main jets 110-130.

At cruise you are primarily using the idle and progression circuits. The main jets and air correctors only really come into play once the throttles are 70-80% open.

Idle and progression are what give you driveability so you need to sort out your low rev issues.

What idle jets and holders do you have installed?
How many progression holes are there?

By all means work on the full throttle jetting but do it after you have fixed part throttle response!

I thought cruise was anywhere from 20% open on ... but now I stand corrected.

FULL THROTTLE is combination of mains and power valve.