Also, since Rinke's in The Netherlands, and Motor West Inc. has none that size, I used a 58 size jet I have, and ran a couple strands of fine speaker wire down through it. It worked pretty good to make it a bit smaller. I later removed one strand, and it's doin' pretty good! I'd suggest maybe even filling it with solder, and then driling it out with a tiny drill bit, but I don't know where to find one that small. I have many needle size drill bits, but none quite small enough... close, but not close enough.
Also I found that mixing your gas a bit heavy with the oil helps a tiny winy bit, but that's not too cool either. Do you have enough back-pressure in your exhaust?