Heres a link available for the cost of googling. 10-12-16g
https://www.shootingtimes.com/editor...loading/361504
I would be interested to see your results if you get something tested.
Depending on the wad and card setup you choose you may have to slightly increase the charge to get the desired velocity, this is only what ive read not a recomendation. This can offset the theoretical lower pressures with fiber. Also, more shot to bore friction and perhaps a less collapsable wad can also contribute. In short, all the variables are in play again so testing is useful.
I like the hard black wads that bpi sells.
Sometimes you get a more open pattern, sometimes not. You will find you have lots of room without a shotcup if you are just adjusting a published load with plastic wads.