BUY a 3/4" ARCH punch. You can get it from Track along with wads, if you want, or about any hardware store can get it if they don't have them in stock.
: Ordinary donacona fibreboard is what most shotgun wads are made from these days. Originally, they were horsehair, then pressed paper, not donacona. - available in 4'X 8' sheets.
: Wad size will have to punch large than .75, or perhaps 12 guage will work OK if the nose of the wad is ground out jsut a bit. That will cause it to cut a slightly larger than 3/4" wad fora snug fit. This is especially important for the heavy card wads needed for overpowder and thing "B" wad for over shot. The card, overpowder wad can be made from heavy card stock like a monopoly game board or others. Check yard sales for these for cheap. Lighter stuff, like tablet backing or cornflakes, etc, boxes are needed for oevershot wads.
: You can also scrounge plastic wads from the trap range, then use a card wad between the plastic and powder, then "B" wad over the shot- done - no cushion wad needed, BUT, you have to have a card wad between the powder and plastic to prevent coating the barrel with plastic.