After a full restore of my MK10 I have experienced and solved some problems that had gave me a lot of work search and head scratch.
Perhaps for some people are evident things, bur for me they aren’t and I will be pleased if I could help someone. I try to syntethize:
In my car stored for 25 years some little corrosion appeared on the metering needle specially in the area corresponding to near closed valve. Replace mettering needles.
One of the float bowl needle seats, threaded to the bowl lid, leaks fuel through the thread, Install the valve seat with some sealant.
Presure of a SU pump is considerabily higher tan the original LUCAS centrifugal pump. This modifies level in carbs. I have installed a pressure regulator.