Trooper, if you have a surplus of wild boar in your neck of the woods, I may be able to get a couple genuine rifles in your hands - depending of course where you are located.
If you have a 10b barrel on order, my 8bore Rodda could serve as a template. It is a little brutish and I’d think that the 10 could be built a bit lighter in the wood.
I also have an Alex Henry 450 and a newish A. Henry style rifle done by Lowell Manly which is set up as more of a match rifle without a rear sight on the barrel, just the tang mounted vernier sight.
Still, either of these with a heavy conical would be superb on pigs!

I’d say that deciding early on if you prefer a straight wood grip with iron furniture or an actual pistol grip stock will help,you lay out what your eye tells you is correct. Of course, both are correct but personal preference will help in this decision.
I do think personally that a straight grip allows you to keep a good heavy amount of wood in the wrist where a straight grain flow will give you the strength you need without needing to find a blank that accommodates the shape of a pistol grip.
Then, with that good strong wrist, the limiting factor in load development is your own shoulder!
I’ve shot my 8bore at 240grs powder which is good for me although the service charge was closer to 300 if I remember correctly.