Best path to “hundreds” of PotD aetherpool?

[Omedon]

The best are widely agreed to be:
MCH
RDM
NIN
PLD/GNB

And, believe it or not, MNK gets an honorable mention.

I assume this is based on a “round them up, burn them down” tactic? I honestly haven’t soloed a deep dungeon before so I’m likely going to read some guides before I sit down to try it.

[Theodric]

I assume this is based on a “round them up, burn them down” tactic? I honestly haven’t soloed a deep dungeon before so I’m likely going to read some guides before I sit down to try it.

For a solo run, the favoured tactic is to take each enemy down one by one. Traps never spawn at the edges of a room, so it's good to get into the habit of only ever fighting in the corridors between rooms and then running along the edges inside a room to avoid triggering any traps. Enemy patrols range from an annoyance to a danger. You should keep an eye out at all times for anything sneaking up behind you.

Pomanders are best saved for emergencies/bosses and a healthy supply of the Deep Dungeon exclusive potions are desirable even if you're playing a job that can self heal as they help a lot with keeping your character alive.

[ItMe]

I assume this is based on a “round them up, burn them down” tactic?

For tanks, yes.
The other jobs are squishy enough that they don't need to AoE down several mobs at once to move quickly, and (sometimes even with Steel) they're generally too squishy for it to be safe to round up many enemies at once, let alone a whole floor's worth of enemies like some tanks can (though admittedly you won't be doing that at less than 99/99).