Balancing Carbs

Been researching methods to balance the Amals beyond the initial synchronization of throttle cables and then mechanically balancing with drill bits/chopsticks. Seems there are lots of videos out there using vacuum gauges and manometers (even quite easy to make DIY setups).
When using these to get nice even vacuum in the manifolds and thus close to perfect idle from making fine adjustments to the slide stop screws....doesn't that then throw any cable synchronization out the window, since one slide is now sitting at a slightly different height then the other from when the cables were adjusted?

Well, into a tune up?
1 All mechanical adjustments-done
2 ignition setting-done
3a idle sync: not... boom/boom/boom/boom... but.... boom/boom/boom/boom
3b power-on sync= 12-15hp(45-60 mph) same as step 3A by adjusting cables- not screws
This is where a brake dyno comes in real handy. Which is a tune up tool not a racing bragging device.
I'd like to see you run down the road at 45+ with a set of gauges or mercury stix in hand tweeking the cable adjusters...LOL
I use my dyno when/if needed.
If nonstandard.... then the thermocouples go in the test pipes.

the use of manometers ( or their equivalent digital instruments) has been a necessity when tuning the <2004 bmw boxer engines. and yes you do an idle sync but ensure you have no tension in the throttle / choke cables. once the vaccum is balanced for the idle then take up the slack on the throttle cables at the carb end...

i have made up a small manometer setup which i have strapped to the front axle on the bmw and do a sync on the fly but you still end up having to stop to tighten the locknuts...

You can get a good idle and setup without a manometer. I have a manometer but tend to use it once I have set the carbs. I now do this with the carbs off the engine and in my hand so I can see what’s going on with the slides. Worth pointing out as well as checking they move together that they clear the bore completely at the same time. For when you have it pinned

What I've been doing for years is first adjusting the slides so that they both clear the body at the same time as I roll open to WOT. Then I set the idle on each cylinder individually - one spark plug wire connected and the other grounded. I set the operating cylinder to idle at 500 RPM using the throttle stop screw/mixing screw then I disconnect that plug wire and connect the other and do the same - 500 RPM. Then, when both are connected, the idle ends up about where I want it, around 1100. Works well for me though it's not a recommended method AFAIK.