Well it's personal preference but I've been well satisfied with Bel Cantos on my rather heavily built carved Romanian flatback.
I like a heavy blunt sound (think Jimme Blanton or Ray Brown, not Chris Squier or Brian Bromberg) and these deliver. I tried a couple different Spirocore (mittle and stark) on low E in search of more volume; they weren't really that much louder and I didn't like the metallic boingy sound so I went back to the Bel Canto E which isn't very loud, but it matches the rest of the strings tonally.
Using strings marketed for orchestral arco play seems to be a minority choice of bluegrass and jazz players, but I wouldn't totally rule it out.
I like a heavy blunt sound (think Jimme Blanton or Ray Brown, not Chris Squier or Brian Bromberg) and these deliver. I tried a couple different Spirocore (mittle and stark) on low E in search of more volume; they weren't really that much louder and I didn't like the metallic boingy sound so I went back to the Bel Canto E which isn't very loud, but it matches the rest of the strings tonally.
Using strings marketed for orchestral arco play seems to be a minority choice of bluegrass and jazz players, but I wouldn't totally rule it out.