For the first mold I applied anthor layer of form release agent (some PVA film material, dissolved in alcohol), which tends to build bubbles, whch won't colaps from appling the resioin.

So the outcom wasn't that nice. IN addition to the the perfect reproduced bubbles other parts of the mold had failing release agent so the outcome was poor:

Left:  mold with the brocken parts of the original    right: perfectly reproduced bubbels.

Left: broken parts fo the original parts      Right: crack between the original backplate and the newpart