I have a Brenneke like mould similar to Cap'n Morgan's and while it works, wad column consistency seems to be the biggest problem I have. I am thinking that really dense felt may be the way to go. Any sort of card wad I have tried as part of the attached wad gets damaged and accuracy is poor.
So far cast on hot melt glue wads have worked best for me. These are for wad slugs, not quite full bore.
I should make some more up and be particularly careful with the wad column.
Cap'n Morgan has made a nice mould for casting his "wads".
My suspicion is that the old Brenneke slugs were fully assembled then a final shearing of the wad to match the slug was done to provide absolute concentricity which I find is hard to do with any screwed on components even when using a jig to align them all.
Anyway, I think this is drifting off topic.
Longbow