In the Federal hull, a 12S4 wad might work. I don't use them, so I'm not sure if they are short enough. I load mostly 2 3/4" shells, once in a while I do some 3". A single-stage is the way to go for these loads. I've never tried any on my progressives, a 600jr or a Sizemaster works for me. With 00 Buck, I use different powders. A 9 pellet load, I've played with Red Dot, Green Dot, Unique, Herco and Longshot. 12 pellet loads, I like HS-7 (which has been discontinued) or Blue Dot.
I get the tightest patterns by taking just the overpowder cup portion of a wad (cut the crush section and shotcup off), fiber or cork filler wad(s) and a nitro powder wad just under the Buckshot. They are a PITA to load that way, so I seldom do it. I get pretty good results using the petal-off wads.
I cast 0, 00 and 000 using LEE molds. Cast with wheelweight, they're hard and pattern tight. I've cast some from pure lead and they don't do as well. I used to by the smaller sizes, T through #1, but the price is so high now that I quit loading what I can't cast.
I started playing with Buckshot just to keep myself occupied some 40 years ago. I'm still at it. Buck, Ball & Buck, Slug & Buck, I can have fun with 'most any load.
DC