After endless checks and measurements with the help of Rui's adjustable push rod, now their length and the rocker geometry are finalized:
I ended up with 4mm shims under the rocker bases:
To install them correct, I needed a set of longer bolts:
Now, the valve stem @ half stroke is spot on in-line with the adjuster!
Next step: shorten the push rods to correct length...
Oh, last but not least, the tig welded, cad-plated fan wheel is back in da house!