Just recieved a call from the machinist.
One of the cylinders needed a +2.0mm piston, so the boring can't be done today as planned.
However he had a set of cylinders, that needed 1.5mm pistons, so I got those for free and ordered a set of 1.5mm pistons.
Luckily I can return the +1.00mm pistons... I just need to send them back to Japan :/