When to harvest horsetails?

So the horsetails have started popping up here (Equisetum arvense), and I'm looking forward to a good harvest this year!

I've read conflicting information online about the best time to harvest, but that's likely as people are harvesting them for both culinary and medicinal reasons, so was wondering if anyone here had any insights.

I'm mainly looking to harvest them for medicinal reasons, so any advice here would be greatly appreciated.

So far I've heard:

If the strobil (initial fertile shoots) are sporing then they've already lost their medicinal potency.
Harvest the strobil, cut off the heads and peel them before eating.
Leave the vegetative until late spring to ensure maximum growth before harvest.
Harvest the young vegetative shoots before they branch out.