What is missing in the bottom left diagram is the bit of metal in the middle that will carry the extractor/ejector, rod/rods.

Personaly I would machine them as the Heym ones by using a flycutter although you will get a slightly different look from the side. perhaps the Heym has side fences? I don't remember. This can be altered anyway by getting the barrel maker to use large stock and then specify the end diamiter. The flats on the insides of the barrels can then be cut to give proper C-C on the firing pins and the correct overhang on the bed.
I think a couple of days with paper pencil and drawing board will save plenty in the long run.

If you want them from EFFEBI then you have to be a dealer. I am in contact with them anyway and can proberbly sort that for you. I have to say though, a pair of round Shillens, Llija etc will be a heck of a lot cheeper. I think that Lother Walther can do it also and I am a stockest of theirs also.

Much I think will depend on the dimension from the bed to firing pin centre as you are governed by this ultimatly. You may just not have enough for diagram 1.

You are welcome to PM me if I can help further.

Regards