Though not a H&H, you do have a paradox and judging by the bores, it is worth a significant investment in restoration. Getting one to regulate is a fairly arcane science. Bell and Seyfried have written articles. For God's sake please do not put a full house slug through it. Probably the simplest place to start would be to order a box of Holland and Holland paradox ammunition which is in production and see how those rounds regulate. My William Evans shoots Seyfried's formula into a two-inch L/R L/R at a hundred yards which is better than most double rifles. I took it to Namibia in '08 and it was decisive on everything from warthog to sand grouse. Restore it and you will have a very special thing.
