Pool size could be measured as a percentage of the network maybe, anyway this is sort of how I see it.

Super Pools are over 5EH in size > 10% of the network each
Large pools are over 1EH in size > 2.5% of the network each
Medium pools are over 100PH in size > 0.25% of the network each
Small pools are over 20PH in size < 0.1%
Tiny pools are over 1PH in size < negligible


None of this is an exact science, but I would think this pool would be more comfortable at or above the 250-300PH mark