Kawasaki H2 750 pistons?

I picked up a barrel and reed block of eBay a while ago but never really looked at it til now with a view to putting a motor together. Upon inspection, barrel height and port sizes, it appears to be a Kawasaki 230 (a) from the Webster tuning manual.

When I bought the barrel it came with an Avanti reed piston, but I think this was only really with the sale as it came with the reed block!
Having a quick flick thru the tuning manual I apparently need a H2 750 piston to suit the set up. Having had a quick look on eBay there doesn't appear to be anything on this side of the pond that sells them... a bit confusing too they appear to be differing heights too!
So, is it possible to source one here? Who sells them if so?
Or, bearing in mind I have no crank or piston at this point is it possible to use the barrel for a different conversion?
Look forward to hearing your thoughts or experiences.
Cheers, Paul.

When I bought the barrel it came with an Avanti reed piston, but I think this was only really with the sale as it came with the reed block!
Having a quick flick thru the tuning manual I apparently need a H2 750 piston to suit the set up. Having had a quick look on eBay there doesn't appear to be anything on this side of the pond that sells them... a bit confusing too they appear to be differing heights too!
So, is it possible to source one here? Who sells them if so?
Or, bearing in mind I have no crank or piston at this point is it possible to use the barrel for a different conversion?
Look forward to hearing your thoughts or experiences.
Cheers, Paul.