When I owned a Busetto (bought from Keith aka Mr Bassman) I regularly swapped between Heritage and Jargar Dolce strings (Keith had Jargars on the bass). Heritage are low in metal content and a decent hybrid string, while Jargars are steels but have in built dampening so they are thuddy and dark,about as gutty as steels can get. I also used Spiro Solos which are low tension but have that more steely, growly Spirocore sound. All 3 worked and it depends on how you really want to use the bass. For slapping, maybe the Jargar Dolces (like Lee Rocker). For more bluegrassy/blues work maybe Spiro Solos? Maybe worth chatting to @bassace or @Mr Bassman