MIRI's current size seems to me to be approximately right for this purpose, and as far as I know MIRI staff don't think MIRI is too small to continue making steady progress.

My guess is that this intuition is relatively inelastic to MIRI's size. It might be worth trying to generate the counterfactual intuition here if MIRI were half its size or double its size. If that process outputs a similar intuition, it might be worth attempting to forget how many people MIRI employs in this area, and ask how many people should be working on a topic that by your estimation has a 10% chance of being instrumental to an existential win. Though my number is higher than 10%, I think even if I had that estimate, my answer to the number of people that should be working on that topic would be "as many as are available."

My guess is that this intuition is relatively inelastic to MIRI's size. It might be worth trying to generate the counterfactual intuition here if MIRI were half its size or double its size. If that process outputs a similar intuition, it might be worth attempting to forget how many people MIRI employs in this area, and ask how many people should be working on a topic that by your estimation has a 10% chance of being instrumental to an existential win. Though my number is higher than 10%, I think even if I had that estimate, my answer to the number of people that should be working on that topic would be "as many as are available."