Maester Steven, may I please ask if you think that the Manpower of the Seven Kingdoms during the Dance of the Dragons or the Blackfyre Rebellion would have been comparable to the numbers available during the War of the Five Kings? (in terms of real numbers, rather than percentages).

Blackfyre Rebellion – definitely comparable; we know that ten thousand men died at Redgrass, which puts it in the same range as most of the major encounters of the War of Five Kings. 

The Dance is kind of weird, because the army sizes are tiny compared all other Westerosi wars. My No-Prize explanation for that is that, post-Aegon’s Conquest, Westerosi divided up their armies to avoid committing their numbers to a single engagement where one dragon could wipe them out.