Look into Bismuth if you can. You don't shoots cases of shells hunting so the cost per shell should not break you. Bismuth 5 or 4's should work well and are kind to old doubles.
Definitely the way to go if the bank balance permits: no need to go crazy in terms of heavier loads
and you don't have the choke restrictions associated with steel (i.e. you can safely put bismuth though 3/4 or full chokes)
and you can use with damascus.
Nice overview of the options here
https://basc.org.uk/lead/ (the Lead Shot Alternatives guide is pretty comprehensive).
We have to use non-tox for 'fowl over here so have put a good number of bismuth through. Never had any problems with cleanliness of kills and, if lead were banned for other game (fortunately not on the cards at present) I'd have no concerns using bismuth.