Unless you're in a real hurry for it, can I suggest you might as well just do fashion report each week and just get it over time? Each week you can get 60k MGP very easily.

Fashion report is super easy now and takes less than 5 minutes to get the minimum 80 score. Usually this involves spending less than 20k Gil from vendors from the items. There's always a thread on reddit every Friday with what you need for the 80 score.

I do appreciate that it's still take 16 weeks (just under 4 months), but it is really is easy MGP and they're not removing Fenrir from the game so unless you're in a hurry.... grinding the moogle dungeons for 600 tokens will probably drive you crazy.

If you use the MGP buff item from squadrons that can even increase to 69k MGP each week and then there's also all the MGP challenge log bonuses, they're not as fast as doing fashion report, it depends on how fast you want it

Just an idea anyway