Needle experts please 300ec AS1

[Dread]

Hi all, I have been experimenting with my jetting and i am getting close to what i am seeking with the N3EH KTM needle.
However it is on the top clip #1 and it still blubbers around 1/4 throttle, I am thinking this is the first taper a little rich?
I would like to be where I am now everywhere else and a little weaker on that transition with the needle preferably on the middle clip , giving me room for adjustment.

Can anyone tell me the next choice? Needle or slide?

AS1 38mm, 40P, 178 air screw is about 2.5 out but engine is not very responsive to adjustment of it. Bike Starts, ticks over, pulls strongly at all throttle openings right through the range with smooth transition to full power but at slower/lower throttle openings it hangs on blubbering too long unless i am giving it more gas by winding on more quickly, at a steady throttle on road it blubbers up to about 45/50mph till it runs cleanly.