If this would help, I've had this info for a while, but kept to myself while I finished the rest of the collection (I was making a spreadsheet of DEF values, resist rank values etc but it's still Work in progress).
For a rough estimate in Sheol C, you're looking at 1300-1350 DEF for floor 4 mobs, it varies, but it's a rough area to go by. (maybe aim for 5500+ Attack for 2 handers to utilise any PDL if no DEF down is applied)
In Limbus it's roughly 1260 DEF the highest value I've seen (Beetles in Apollyon), on 130. And around 1340 to 1370 DEF on 135. For the 119 I think they were around 970 DEF or something, trying to go by memory for the 119, but it's around there.
(The DEF values I provided were the highest value I could find in each content as of right now, some mob types have lower, but I figured the highest one would be more beneficial.)
In v25s, we can use the Arebati thread that lists his DEF value somewhere around 2695 The rest of the V25s (T3s) have quite similar, varying by +/- 200 DEF depending on the mob (I don't have exact values off hand, sorry)
I hope this is remotely helpful, most of the values are rounded up and not 100% precise due to that, but it's a general ballpark to look at.