Thank you both for your replies. As they tend to be something that doesn't really wear out I was wondering if anyone had a set kicking about before I buy new ones.
VM22/210 is the type of jet - they're to go in my VM29 Smoothbores on my Z1000J. 25 is the size Mikuni recommend for a thou and a good starting point, where my current 15s are definitely too small as I have to wind the air screws right in.