DF-
I don't know who Don Zutz is.
When I make wads or cards, I either take one of the twenty or so arch punches I have and whack away, or if I need a size I don't have I make one from stock.
Of all the punches I own, I think only one of them is marked with a firearm-specific diameter.
I cut my felt wads 'a bit oversize'
I build my cup-card OP wads to have a slight interference fit with the bore -- we're simply after a good gas seal.
For felt stock I shop from McMaster-Carr or from a local equestrian supply shop (saddle felt), typically the thickness I use is around 1/4"
In the bore rifle cartridges there is little room to fill, so I'm not aiming to fill space - rather I build my wad column to maximize consistency and to maintain bore condition shot-to-shot.
The 'filler wads' as you say, are typically a simple disc and donut stack, or just a donut - on top of a cupped card over-powder wad.
The over-powder card sits with the cup facing the powder.
The felt wads have the donut against the ball, the felt disc against the card, when present.
I do not use hard fiber filler wads at all.
The pressure on the powder is uniform for all of my black powder cartridges. No compression that would cause a bullet or shot column to creep at rest, yet firmly tamped in the hull or case.
--Tinker
