One of the delights of New Zealand is that the riding is amazing. One of the downsides of New Zealand is that postage costs are ridiculous.
Stark wanted $1 for each of the copper washers that you replace with each gear oil change. That's reasonable. But the postage was $53. That's not.
Hence here's the copper washer dimensions so you can pop along to your local motorbike shop and avoid having to pay shipping:
Gear oil drain plug washer - OD 16, ID 10, thickness 1.4
Gear oil level bolt washer - OD 8.8, ID 5.4, thickness 0.9