Hey there mate, the PHBG 19 AS would be perfect; mind that the PHB type carburetors can be nasty ones to tune, but it will def yield you more power than the SHA or the NT. Refrain from buying those chinese imitations, Dell'orto's name alone is a warranty:I understand what you are saying about extra hole, hole positions etc. I'm waiting for other jets to test them. If then is still not idling, I leave the nt type.
EDIT: What would you recommend, a Mikuni VM18 or a Dellorto PHBG 19mm?
I can get you a genuine one straight from the factory, here in Seregno, Italy.