This is a fun way to wreck Odin as solo Aerith
HP<=>MP materia gives you extremely high limit break gain. Also lets me cast Cometeor freely (costs 37 MP). Enhanced Expeditionary Medal is why I can cast Planetary Protection right at the start. Ceremonial Staff gives me 2x Altruistic Buff which is necessary for PP to last this long.
I'm thinking of using this baseline as a variation for a NG+ hard mode whenever Aerith is in the party. A more stable variation would have a separate caster that uses the HP<=>MP materia and Aerith equipped with Limit Siphon instead. If you're good at getting the synergy blips on Aerith and can skip the need to use Expeditionary Medal for accessory slot, you can further buff how long Planetary Protection lasts with Enchanted Ring, and "Selfish Buff" on other party members.
Full quality video on YouTube: https://www.youtube.com/watch?v=cm-56MP4BF0