At the moment I am playing with a cheap bow (with equally cheap hair) and Spirocores (double red winding, not sure whether they are Orchestra or Weich) and I am trying to improve my arco sound. Admittedly I have not been playing with the bow for very long and I don't expect any change I make to suddenly solve all of my bowing woes, anything I change will be accompanied by copious practice. With that said, I don't want to be fighting my bow or my strings trying to get a decent sound, so my question is: what should I change first? Get a rehair for my bow, or change to a more acro friendly string, or is there something else that would help?
. But the rosin switch made a big difference in my case. YMMV.