I have been MIA with a similar thread with DCNF downdrafts. There are many issues in common with DCOEs and most of what I wrote was based on Keith Francks observations and my previous modifications of weber DCOE 42 -9 carbs on my 240z.
https://www.ferrarichat.com/forum/308-328/423336-dcnf-progression-tuning.html
Durrag, the size of the furthest progression hole from the engine will influence the richness of the initial hole/s, and it may be easier to slowly enlarge this hole as a "dynamic air bleed" than to fill in or wire the 2nd progresson hole.
Cheers
Rob