I finally achieved my goal.

The latest QOL updates to DQM3 finally let's you see sizes so it becomes pretty easy to make a large monster.

Quick takes: You previously had a 1/10 chance to get a large monster with the matchmaker in Fortitude Lower. You now can make it a pretty much 100% chance with the current update.

Also the Cane Custodian monster that was large in Indulgence literally without a large monster you had a 2% chance to create a large monster with a small one.

I will say there was horrible recruitment luck across the early game. I for the life of me couldn't get a Bongo Drongo to join this time. I probably had my best middle echelon ever to make up for the slow start. Other than that it was mostly cleaner boss fights though I forgot to heal on Randolfo 1 so lost a bit of time on the final boss.