parqer4 days ago I was also wondering this actually. Seems like there are too many missions to justify ILs for each, but an IL per chapter seems more reasonable
I'm actually making slow progress on IL/C splits for each chapter. the IL/C split i made for chapter 1 was posted earlier today as a practice split which you can look at as an example of how i'm currently handling setting them up. as they are for practice the split ends at the same point as it would in an actual run rather than when the boss of the chapter is killed.
depends on how you want to handle the arenas, they cant be autosplit in the normal manner as they all share the same flag, so they would have to be manually split, you'd also have to be in a certain section of NG+ to get 2 of the fights to even show as they aren't there in NG, and go away in NG++ iirc.