Please allow me to be lazy ’cause when you look at them individually, you can barely tell the difference.
#1 and #2 are relatively bluer green in comparison to #3 and #4 are more yellow green. The facts about those inks are similar, saturated color, not so much shading, roughly 10 sec for drying, and didn’t bleed through iPaper UCCU or DoubleA. Somehow they showed water resistant slightly but mainly because of the iron gall. When dropping the water, the green color was washed out immediately and leave the trace of iron and paper reaction.
For collecting sake, yeah, why not get them all? But if you just want 1 and only 1 bottle of green, I might choose #3 as it’s slightly harder to think about other ink that similar to the color.
CP value: 77/100, you really don’t need that many greens in your office