I have close to 300 hours on my jbs 105mm liner and piston in desert conditons CR is 11.8:1
bit of blow by out the breather now but it still runs rings around my worked 628
Unfortunately Ben isn't interested in selling kits anymore so we have to organise things ourselves
not difficult .. a few people in oz have done so already, westwood does the liner from a model I did up, then you have the piston built to your own specs from JE or CP.