Hi Alan.

I have loaded with WAA12H wads for many years now & they are most definitely 1 1/4 oz wads.
I'd suggest getting hold of a copy of Winchester's reloading manual which lists several good loads.
Dont try to load too high in regard to muzzle velocity. Anywhere from 1220 to 1300 FPS is plenty for a heavy 1 1/4oz load, although lead shot is no longer acceptable for duck hunting in Victoria. My own loads are only 1230fps & will kill reliably to 50 yards with ease. I only use these for foxes these days having switched to Bismuth for ducks.

As an aside, I also load home made Bismuth shot for ducks, using the WAA12H wads.
Bismuth is readilly available in ingot form, albeit costly (last batch I bought was $35/kg with min of 5kg ingot = $175 for 5kg)
I have a shot maker & make my own shot by mixing it 4% with tin.
I then use the WAA12H wad to load 1 1/8oz of bismuth shot.
As the Bismuth is marginally lighter than lead, 1 1/8oz will load by volume into the same space as 1 1/4oz lead. I use a standard 'stiff 1 1/8oz load (I use Vectan D20 powder over Win 209 primer).
This gives me a MV of approx 1280fps at a modest low to mid 9000+psi pressure & it kills brilliantly.
Anyone that can tell the difference between these loads & a good lead load is a better man than I.
Easy to load, good on barrels (no need to open chokes out, etc with Bismuth), good on the shoulder, & just work damned well.

Bill Allen
Melbourne Australia.