Sounds to me like the carbs are not as clean as you think they are !
definitely a carb problem if you can block the intake /air filter area and it's better.... I've said it before and I'll say it again these carbs are the hardest to clean of ALL Motorcycles ! it sounds like the carbs are dirty at the same place on both motorcycles.... think about it.... you cleaned them in the same manner
and the junk moved to the same spot in the carb and plugged up....
..... I suggest you clean the carbs again !
I realize you already did all that BUT .... it's not running right and it seems to be carburetors.. so..... do it again, but this time be extra sure those passages are clean.....
I think Ducattiman Uses Soda Blasting on the carbs that may well be the ONLY thing you didn't do.... and may well be the reason it isn't working
I feel for you.... all that work and their not right must be frustrating ! but keep after it ! you can do it !
.....
Bob....