I have a shoot in a large office that is lit entirely with florescent lights, and I need to pick up some gels to shift my tungsten lights so they match the rest of the office. In the past, I have gelled the florescent lights to remove that nasty green. Unfortunately, correcting the florescent lights is not an option here, as there are far too many of them.
I know these gels need to be blue-green in color, but I can't seem to find a straight answer on which gels will work best for this. Do they make standard gels that turn 3200k to 4300k? If so, where can I find these?
This is a common issue and has been dealt with scores of times before here on the lighting forum (feel free to peruse the archives), but put simply, gels on your tungsten lights rarely succeed. The issue is the the overhead fluoros are discontinuous sources, that is they have a green "spike" and the plus green gel you would put on your movie lights create only an overall greenish light.
The best and most elegant solution is to beg, borrow or steal some of the same tubes that are installed overhead and use them as "poisoned lights" in four foot kino flo instruments. This way all the lights have the same quality and white balancing your camera corrects everything.
The only other advice is to be careful with the overhead directly above your subject(s), you might want to flag or turn off (by unscrewing) panel(s) directly above to minimize/eliminate bright noses.
What John said. Gels over tungsten lights doesn't always give you a correct color (see "discontinuous sources"). Lamping your video lights with the same tubes as are overhead will at least get all the lights on the same page.
If you go with the overhead fluorescents and the "poisoned" kinos I would highly recommend a Tiffin FL-D filter (or equivilent). This filter is designed to counter the green spike in commercial fluorescents. It looks very magenta, but if you white balance through it under fluorescents it restores a lot of the natural color.