I frequently find some useful white or grey in the frame. Anything that should be neutral will work although darker values are more problematic. I take it you're referring to the Abobe converter, thus the Tint reference.
For macro I think the settings are pretty constant depending on distance to the subject. If I didn't have a white, I could set based on how close I was. I had one shot in particular that I just couldn't set. There was no white reference and the colors were completely off. Turns out the strobe altered the colors of everything in the frame. In the future I'll try (in those cases) to shoot an extra frame with a white reference. An alternative is to set custom white balance like Alex is doing.
Back to the tint. The tint value of +100 indicates that you feel there is consistently too much green which is exactly my experience. Problem is that +100 is pegged. On my last trip I settled on using B+W FL-D filter which is a very pale pink. It provided and equivalent of about +20 tint along with a similar lowering of of color temp. As a result, I was operating at [3600K,5500K] and [-20,+20] rather than [5000K,7000K] and [+00,+40] without it. This was macro, of course. Further distances produce much greater differences and require stronger filters. In any event, if you find you consistently use conversion settings on the far end of the scale, you might consider experimenting with filters. Another triumph of digital.
Without filters and with greater subject distances, my experience is the same as yours, Simon. I think this is a very interesting subject, and the Adobe plugin gives its users a common language for discussion. BTW, positive values of tint roughly correspond to CC units of magenta filtering, i.e. +30 tint matches a CC30M filter, and negative tints correspond to green filtering (CC30G). If I'm wrong on that hopefully the Adobe rep will correct me.
