Foxtails are a good indication that the plant is close to being finished, But to answer your question depends on the strain. Your strain "early 90's Super Skunk" should still have some foxtails on it when you harvest if your goal is 30% amber trichomes. 30% amber trichomes being the point I harvest no matter what anything else looks like.
LOL! Ok, 30% of what??? Every new foxtail it's like "trichomes? those are rookie numbers! I'm gonna bump those up!"
I get what you're saying though. they are about 50% milky right now and it's obvious to the naked eye, so hopefully when the ambers kick in hard it'll be obvious too. There's probably +/- 1% now, scattered and mostly on leaves, so it's starting.
Do you think the older sugar leaves might be a better indicator?