I last requested for advice in the Weekly Questions Megathread here, about a week ago. Since then, I've done the following:

• Gathered enough ability tickets to get Fat Chocobo to max out his Barrier ability, and unlock all skillseeds (21 tickets used).
• Unlocked all of Fat Chocobo's extra skills (3 Extrangers used).
• Managed to unlock a couple of panels on my Mage 4th Panel. Image here

I've managed to beat up to Floor 65, and I am currently finding Floor 66 to be a rather impassable wall. My current deck is as follows:

• Earth PuPu 4* Lv29 (EnEarth Lv3, 0 extra skills unlocked)/Fat Chocobo 3* Lv24 (Barrier Lv4, all extra skills unlocked)
• Fafnir 3* Lv26 (Blizzard Lv4, all extra skills unlocked)
• Cockatrice 3* Lv26 (Aero Lv4, all extra skills unlocked)
• Yuna 3 * Lv26 (Cure Lv4, all extra skills unlocked)

I am finding that using Earth PuPu seems to give me a more stable outcome than using Fat Chocobo. This is mainly because on average I usually generate around 2 Health orbs at any one time, meaning the uses end up being split between Fat Chocobo (DEF up, lesser heals), or Yuna (raw heals, nothing else). Earth Pupu ends up being an unused slot, but he's mainly there for the innate Earth-elemental resistance.

Is it possible for me to go any further on the tower? 65 kills is currently Rank 8876 at time of writing. I'd like to try and keep in the 10k range if it's possible, but if it's not, I guess I won't sweat too much over it.

I currently have about 1300 Magicite, so I can consider getting a pack of 5x Silver Openers for 1000 Magicite if that is one of the better advice. I already have a Mobius Box, which is valid for another 21 days.