Mikuni TM40 - pumper nozzle?

I really happy with the performance of the carb apart from when snapping the throttle open where there can be a moments hesitation due to over fuelling. This really knocks confidence when dropping down rock steps or attacking the steps going up as it can result in going over the bars or not making the step. As I have said jetting otherwise is fine and very clean so I am fairly sure that it is an issue with the AP circuit
I have the AP 70 nozzle, which is fitted as standard and am just wondering what size nozzle others have who are using the TM40 on the XR?
Choices are 35, 45, 55, 70 and I've seen a post somewhere on the net mentioning the 70 is for the big Harley motors and 50 being the one to fit for big singles which is puzzling with only a 45 or 55 to chose from.

Also got the 70 Hew, and no over fuelling/squirting here!
I'll admit that I went though pains to get it adjusted like that, with I think ~1.5mm 'free' play at the bottom, but I'm happy.
Oh, no, never tried another size as I don't have one, the carb came with it (XRsOnly) and I got it to work.
If yours stumbles when snapping open then perhaps get a bit more free play in?

Edited: of course I've aimed the jet to 'hit' the needle, in fact it hits it on the RH-side when looked at from the filter's side. No idea if this makes a diff but hey, anal is me

Cheers Burp,
I have adjusted the start point a full turn but no real improvement.
As I say the carburation is very clean and it rips when wound on. It is just the ditch and log jumping throttle snatch that it baulks at and has a slight hesitation.
I'll keep on playing with it.