Pick the mark, then publish it.

The trade

Shorter marks bill more calls at a lower price; longer marks bill fewer calls at a higher one. Neither is "right." A 20-second mark on social traffic bills a lot of short conversations; a 60-second mark on CTV traffic bills only the ones that turned into a real pitch. Agents will pay more for the second kind.

A working method

1. Pull talk-time distribution for the line from the console (calls → filter by line → export). Look at where the drop-off cliff is.
2. Put the mark just past the cliff. If most dead calls end by 12 seconds, a 20s mark bills nearly every real conversation and almost no junk.
3. Price to the mark. A higher mark deserves a higher price; agents are buying certainty.
4. Publish a ladder when the traffic is mixed — 30s at one price, 60s at another — and let agents choose the rung.

Common marks by vertical

These are starting points, not rules. Your own talk-time export is the only source that matters.