I forgot to show the characters stats - Rikku, Tidus, and Wakka all have 255 Strength, Magic, Agility, Defense, Magic Defense, and Luck and base stats for Evasion and Accuracy, while Yuna just had around 240 in all stats (minus Evasion and Accuracy which were base) and about 70 in Luck. Rikku, Wakka, and Tidus all had the same accessory - Break HP Limit, Auto-Haste, Auto-Protect, and Ribbon.
I kill the hands just before their turn and when they are dead, focus on Penance. I use Rikku's Mix to cast Ultra Null-All to help reduce his damage, and use Quick Hit to get in more hits. In his second form, I caste Dispel to remove Armor Break, though sometimes I forgot to do this which resulted in my characters dying sometimes, and I had to summon Anima due to both the arms being alive and Penance about to have his turn, which resulted in him casting Judgement Day. Without mistakes I could have beat him around 30 or 33 minutes probably (I sometimes forgot to count how many times I hit his hands).