Am I missing some good music?

Like others who have posted here, I don't want to miss out on any good music during the 10 days we have in Vienna, end of September-early October. We already bought our tickets for the opera and have bookmarked the Sunday masses at the Hofkapelle and Augustinerkirche. Sadly, St. Ignatius doesn't seem to have any scheduled during our visit; likewise, the giant organ concerts at St. Stephen's have a gap from Sept.3 to Dec. 29. We will go to St. Anne's but I couldn't find a concert with period instruments (we're early music fans) for a night that works for us. We'll drop into St. Peter's for an organ concert, but the evening performances of Classic Ensemble Vienna seem a bit kitsch. We're also thinking of hearing Mahler's 9th by the Vienna Symphony Orchestra (we usually prefer chamber music but can't resist Mahler). Unfortunately, the Philharmonic's program doesn't appeal. There's also the West-Eastern Divan Orchestra, which I've never heard of, directed by Daniel Barenboim at the Musikverein and the Rising Stars series with the Janus Quartet in the Schubert Hall. Any thoughts on these last 2? I really don't want to hear another 4 Seasons (St. Charles). We probably will also do the backstage tours at the Concert Hall and Opera. There’s so much else going on while we’re there (Open House Wien, European Heritage Day, the Vienna Wine Tour, and the Long Night of the Museums) so it’s already hard to fit everything in. A great time to visit Vienna.