this might be obvious, but i always tune these by going off the screw, on the PWK clones it is an air bleed so if i'm less than 1/2 turn out (going in is richer) i go down a pilot jet, if i'm more than 2.5 turns out (lean) i go up a pilot jet. if it makes no damn difference at all i just swap parts wildly until it does.
i can't give you the answer you want because i haven't played with the polini specific ones yet, but 32-38 seems to work for every single pwk style carb i put on a moped.
i'm still figuring them out, trying to tune in a 24 joko on my tccd 70, but the needle seems to really rule the roost, clip changes make a huge difference. I just bought a new genuine oko needle and atomizer. Your results may vary though because i'm on a cretin-ported piston port with zero midrange, and you're on a bike that is going to have a much flatter vacuum signal.
good news is that all the PWK clones seem to be super stable jetting wise, there are really only about 3-4 pilot sizes and jet sizes that apply to mopeds, i'm not totally scienced out on the needle thing yet but from what other people have posted, it seems like the needle and atomizer that comes with them work for most setups.
let us know how it goes, i'm gonna put another joko 24 on my parmakit a35 next.