Arcane Sight and Spell Idenfitication

[Splendor]

Party is getting close to the end of the adventure and should be 17th level when they fight the big bad. They will know they will be facing him (and maybe some minions) and only have that single encounter that day.
Knowing the PCs they will buff all out before they go in to fight him.
He'll have permanent arcane sight... Is there a limit to how many active spells he can identify per round? Or will he just know each of the 20+ different magical auras on each character are?
I am looking at him using greater dispel magic to target specific spells, like spell immunity, deathward, ect to just ruin any of the PCs plans.

Quote:

Greater Dispel Magic

Targeted Dispel: This functions as a targeted dispel magic, but it can dispel one spell for every four caster levels you possess...
Dispel Magic
You can also use a targeted dispel to specifically end one spell affecting the target or one spell affecting an area (such as a wall of fire). You must name the specific spell effect to be targeted in this way.

[Chess Pwn]

I'd say there is no limit. If they are within sight he gets to make spellcraft for each right then and know all that he passes.

You can see it as identifying animals, if you know the animal you recognize it on sight, but if you don't know it then doesn't matter how long you look at it.