I agree with Andy. I would never use a tapered wad in a straight walled hull.
Tim- Check the Alliant site for reloading data. You can use any data listed for Red Dot interchangeably with Promo. Remember, reloading guides give a list of safe loads. You have to select the best loads from the list.
I agree with Bruce. Using a Rem Gun Club hull, Rem STS209 primer, 16.2gr Promo, either a Fed 12S0 or a DRM XXL Pink wad and 24g shot I get just under 1200fps. Going to 7/8oz of shot should give you about 1800fps.
I don't want to mess with card or cork fillers, so I use the Gold Medal hulls for bunker loads where I need the extra room they provide.