I would think that either adjustment should work – I have never had carbs with an adjustable needle but do have 40 years or so experience with adjustable jets so that system was more familiar to me.
Do the adjustable jets, perhaps, offer a wide range of adjustment than the adjustable needles? I vaguely recall more than one post stating that their adjustable needles could not be moved enough to lean out the mixture as much as they wanted.
-David
I have the adjustable needle and ran too rich. Only way I was able to improve the situation was to tap the jet upwards so that the distance from the top decreased from the rec .1 - .125 inch to about .5 inch range. Probably a lot easier if I had an adjustable jet.
Abe
My Joe Curto setup adjusts from a minimum jet depth of .070" to a LOT deeper - possibly .400" . I am running them at .125". Its a very easy adjustment- slotted hex bolt under the bowl, a la SU carb.