I say it depends on the Bass as much as the player. I have Weichs on one of my modern Italian Basses currently (G.Lombardi, 1976) and it bows kinda good. Too good to change the strings actually. I had Weich Spiros on my Bohemian bass as well (which I just sold) but that was not as deep a bass for bowing and it didn't sound quite as good but it worked. It was my Jazz instrument so I didn't care how well it bowed.
Years ago when there were ONLY Spiro Reds or Rope Core Blues (can you remember that far back?.. maybe there were solo Spiros, not sure when they came out), I used the Reds on my old Italian Bass for every thing I did. Sure, I tried some other strings and my Bass was also with me in hand the test bass/player for the Labella steels back in 1978 or so. Rotosound even made an Orchestra string that for me, was lighter tension but more of a Jaegar feel string than a Spiro. The Reds were in the middle for me so that was my go-to string that I used the most. If I had a bowing job, same bass same strings. Jazz gig, same same. So, with the Weichs out now, they make it easier to bow on lesser basses than the old classics whihc can sometimes work and sound as good with anything from pure rope to barbed wire.
One thing though I want to mention. If the strings are too flexible on your bass, when you pizz like in jazz and you start to dig in harder, you might find yourself chasing the beat as they respond slower when played hard. For that, Reds are better.