This is from champs parts list..... I think you will have to email them to get a discount. They are in Japan but pretty good with the service
VZ115-20 1st gear 20T 525 yen VZ115-21 1St gear 21T 525
VZ115-22 1st gear 22T 525
VZ115-23 1st gear 23T 525
VZ214-15 1st gear 15T 525
VZ214-16 1st gear 16T 525
VZ214-17 1st gear 17T 525
The first 4 i think are 2nd but this is how its listed.......... dunnno ??
BTW why would you need so low gears ??