As concluded in the last post, I did chose to use spacers under the cylinders in order to get the deck height right.
However sources for 30/36 hp cylinder spacers are not as plentiful as for the more modern engines. Wolfsburg West do sell barrel shims for the early engines up to 1.5 mm in thickness. But, to retain the deck height (69.5-64)/2 = 2.75 mm is needed on each side.
The only way to reach to this measure with WW's shims is to stack two on top of each other. Stacking means more surfaces to seal from oil leaks, thus a single one is a better choice. But, where to find someone who can custom machine a set with the desired thickness?
To my rescue came vintage VW tuner Mats from Östergötland, Sweden. He made me a set of four spacers with 2.7 mm thickness with perfect fit and finish. I now have 1.3 mm deck height, which is what I did aim for. Many thanks Mats!
Next step is to put in the Wolfsburg West extensions for the push rods.