what i did was that-
normally i used arthur as my soul 'cause she could do burst attack on the first turn+got attack boost from that SSR winds axe, also used ambush ability to decrease defense.
so when i joined a battle i used all of her abilities and then did auto battle (not auto ability, just auto)
when i started my own expert, i usually didn't request for help so i can get around 20K PP per battle.
when it was burst time i switched my soul to siegfried and either helped to grt her hp down till she is stunned or just waited for her to be stunned so the battles ended quickly.
i joined some ragnarok with a few players (some of them with kitty here) so i could get around 30-60K PP in those battles (used andromeda with black propaganda to survive longer lol)
and sadly i had to work and play with my phone during this time, so couldn't join any battle 'cause the connection is bad so did only some standard while i was there, and then when i got home used my seeds and ap for expert.
that pretty much how i played during this event