What you have here matches closely with I have been wrestling with. I do a lot of work on college campuses, and I need to blend flash with ambient all in one file in the camera.For balancing flash to fluorescent, it really depends on which type of bulb is in the room. Lots of rooms on our campus use Warm White Fluorescent, which is about 3600K and has a color correction of ~24 magenta in Lightroom. Balancing a flash requires a Half or Full CTO and about a 1/2 so Plus Green (green filter.) That gets in the ballpark.
Other fluorescents might be 4000-4400K, or even "daylight" at 5000K or so. Almost all of them will require some green over the flash to balance, but different amounts of orange, or none at all. The key is to test, then test again, and keep copious notes.
Also note that different flash units will require slightly different filter packs.
Johnathan Wienke in 2005 had a post (below) I found really interesting and helpful. I have used variations on what he outlines here and made my own gels for canon strobes with with some good results with compact florescents.http://www.luminous-landscape.com/forum/index.php?topic=4417.msg36426#msg36426
Yes, there are a million different flavors, and for me it usually mixed light, something interior photographers correct with layered files.
I have never tired mixing green with a cto. It does make sense when I look at corrected white balance adjustments in Lightroom. I'm looking now at a corrected file in Lightroom is showing 2950K and +7 on tint. (Does 7 tint equal 7cc on filters? I probably knew that for sure at some point.) I have found that Cut to Straw (CTS) can be a better match to the ugly yellow/orange that passes for warm in warm florescents.
I have a bunch of 30 green gells from back in film days. I have found them way too much green with digital and light out there now. I'll have to find my old rosco sample pack and try some paler greens.
thanks everyone, this has been useful, John