So I don't have a clue about building engines, or the exact specs for pistons and cylinders needed for different size Type 4 engines, but I happened to see these on EBAY, and I figured I'd post the link here in case someone might need these.
...to me, provided they would be useful for someone's build, they look like they are about a grand cheaper than usual. Hope this is useful....maybe some more knowledgeable members will chime in with better info on both price and usability.
https://www.ebay.com/itm/LN-Engineering-VW-...QkAAOSwvqdeqOAK
Hope this helps someone!