Some Sud/33 carb advice.
Webers are easier to set up than Dellortos. This is because Dellortos have air by-pass screws. The plus side is that properly set up Dellortos will be smoother and sweeter than Webers.
Here's the 'screwdriver only method' for Webers.
1. Remove the air box. Plug the small vacuum hoses from each inlet manifold so they cannot draw air.
1. Disconnect the throttle linkages to each carb.
2. Wind back the idle screws until each carb is fully shut.
3. Wind each idle screw up by exactly the same amount (perhaps 2-4 full turns of each idle screw) so that the engine will start and idle.
4. Adjust each idle screw by same amount (small adjustments at a time) until satisfactory idle speed is acheived.
5. Re-connect the throttle linkages.
6. Turn throttle bar and observe contact between the balance screws and the actual carb throttle lever. Adjust one or both balance screws until each cylinder bank picks up at the same time.
7. Turn of engine. Whilst ooking down inside carb, have someone operate the throttle pedal right to the stop. Ensure both carbs are reaching max opening.
If you are still having problems with flatspots are hesitation, you may need to check the jets (particularily the idle jets) for water or blockage. The idle jets also control low speed/low throttle opening settings (progression) and are more prone to blockage due to their smaller size.
For a more accurate set up or for Dellortos, one of these is handy:-