I recommend using #5 lead shot for upland game. You are in a good pheasant and rabbit state, and you do have some rufted grouse, too. Take a look at The Track of the Wolf's website catalogue to familiarize yourself with available wads. I do not recommend using shot cups with lead shot. You will need special heavy shot cups for the Bismuth or Steel shot for goose hunting, and that is best bought through Ballistic's Products. But compare other suppliers on prices. I know that Ballistics Products came out with the heavy gauge plastic wads to protect barrels from steel shot, and have lead the way.
Use FFFg Goex Black Powder in that gun. Buy a couple of extra nipples for replacing those on the gun, Just in Case! I don't recall you listing a nipple wrench, or a wire to clear the nipples, or pipe cleaners to clean the flash channel, but you will need them. If you buy an Adjustable Powder Measure with the attached funnel, like sold by Track, and made by Tedd Cash Products, there is a wire in the bottom of the measure, attached to the knurled screw head, that can be used for this purpose. Sometimes you do get crud stuck in the nipple, and that can stop that barrel from firing until you clear it out. If you carry the wire with you, you can clear the nipple right then, and go on shooting.
Measure the Inside bore diameter of both barrels with a caliper, to be sure just exactly what diameter you have, before ordering Wads. If you buy cushion wads, you will find, as most of us have, that spliting those cushion wads in half or thirds, provides enough surface to lube with a liquid lubricant, ( moosemilk, or olive oil) while keep the weight of the wad low enough that it does not follow the shot column and bump it, in midair, causing a hole to appear in the center of the pattern. Using the full !/2 " cushion wad soaked in any fluid will generally cause the " donut hole " patterns. Since you have two barrels to load, simply split the lubed cushion wad, and put one half in each barrel.
You might try looking back many months for Jim Rackham's post here about using only OS cards to load his gun in the field. He puts off center holes in the OS cards, using an awl, before the hunt, and only carried those wads. He uses 4 OS cards in place of the OP wad, and the cushion wad, putting the holes in the cards so they don't line up with each other, then his shot charge, and then 2 more OS cards. He finds( and I found) that using 2 os cards made sure that the shot charge in the second barrel did not move forward during recoil from firing the first barrel. Again the holes are in different locations. On leaving the barrel, the holes allow wind to separate the cards, where they fall to the ground quickly and do not follow the shot charge. This simplifies loading in the field a bunch. To Lubricate the bore, I carry pre-lubed cleaning patches in a plastic bag and run a lubed patch down the barrel on the jag when I seat the last 2 OS cards on the shot. The lube protects the bore from rusting while I wait for the next flight of birds, and softens the fouling for easy cleaning between shots. I carry cleaning patches in another pocket.
The only use I now have for my 1/8" thick OP wads is when shooting RB out of the shotgun. The cushion wads I still have are looking for a good home. 12 gauge.
