We need to come up with a single-track opinion of priority.

Goal of this stage: force more hard choices. Synchronize priority across the org (or at least across this resource pool)

Have one person from each team, plus the owner of each distinct system (to speak to tech debt priority), plus the heads of product, GTM, and engineering represent their priorities in a Hunger Games session to make a combined now, next, soon, later. Make it very, very clear to people that this is their last change to argue priority. If there are tough conversations to have, they must be had now. Everything past this point is going to just be science and math.

Stop when, even though you haven’t t-shirt sized anything yet, it’s blindingly obvious that nothing you add further is going to be done any time in the next ~4 planning periods, anyway.

This should be bloody. If there isn’t a lot of argument and consternation, then you’re doing it wrong and should seriously examine why.