[wwb]

The Winchester 20F1 wad has been out of production for several years, and is nearly impossible to find.

The Remington SP20 is the current wad of choice for 1 oz 20 gauge loads in a Remington or Winchester hull.

Load data is available from any of the powder manufacturers.

 

[wwb]

I shoot 3/4 oz loads of #8-1/2 in the 20 gauge.... and I shoot the 20 in the 12 gauge event, as well; no need to go any heavier than that. As DLM alluded to earlier, the .410 is where you separate the men from the boys.

I suppose there might be a slight advantage to shooting 1 oz of #9 with a slightly more open choke, but I'd prefer to shoot the bird rather than shoot AT the bird.