Hogdon presently lists six loads in their current on-line load data using 800X for your hulls that should both fit and function just fine. For the loads listed as producing 1200 fps, you can back it off a bit on the amount of powder or call them to verify that's okeh, if you wish; shouldn't be a problem when all else is kept the same as listed.
You'll see or hear where some folks complain about 800X's flowing characteristics, to which I say both 'bunk' and that they were likely using manually operated progressive presses and had every effort based on absolute speed. If you take a moment, or are using a single stage press like a MEC, the 'flow' issues will be zero.
I'll also mention that 1oz. loads in 20's are much like Ted says, when you go to pattern them, 'hit or miss'.
I've a friend who swears by Hogdon Longshot and there are 7 of the 9 loads listed that meet your criteria as published. He loads on a Spolar that is plenty quick and uses the Remington SP 20 wads w/o issue. Both he & his son took multiple limits of dove using those loads W/# 7.5's during this past season and seasons past. He son routinely uses the same loads in a Beretta gas gun for sporty clays & posts good scores w/them. I've no personal experience w/that powder or using his loads, but have witnessed many a dove bagged and clay broken w/them.
I still prefer shooting 7/8's oz. rounds of #6's in a 20 for dove, quail, cotton-tails & feral pigeons. #7.5~9 for clays & skeet. Don't shoot a 20 at trap, tho some do.
Of course, Joe Wood has seen me miss a flushing bird more than once, that had nothing to do w/payload or shot size whatsoever and can verify that fact. It was because he pointed out that the bead on the model 31's adjustable choke devise I was shooting that day was ever so slightly to the left! I'd been killing birds w/o thot for years prior w/that gun, never once even had a conscious awareness that the darn thing had a bead! Clever, these old guys w/hammer guns; don't get side tracked w/minutia, take the bbl. or bbl.'s to the bird & shoot it!
And I still like seeing what a few patterns look like on a grease plate, but that's just me.. and you and whole lot of other like minded individuals that like to shoot and have a keen interest in shotguns and their voodoo.
Pull!
'Take 'em!'
Very glad to see that you are back up to speed and not bored stupid. Find that load you are seeking.
FWIW, an old bud of mine, 96 now, took to cutting the cushion section out of some AA20 wads & turning them around, effectively making them 'shorter'and two-pieced when playing w/1 oz 20 ga loads. They were pressure tested by one of the major munitions makers at the time; those found safe/within SAMMI specs. got shot at clay targets, more for amusement than anything else. Neither of us was fond of 1 oz 20's, excepting for ducks decoyed in close. It was still lead shot days then and not that many guns were chambered for the 3" varieties that Francis Sell was such an advocate of. We took early season teal decoyed in close and some passing well outside the decoys w/1 oz of lead 6's w/o much difficulty using the better loads and a 20 ga. was a lot less burdensome taking into some of the playas we hunted back then.
