Arc the Lad 2 - Diekbeck EXP farming

I am not making that infamous joke...
The interesting mechanic about Diekbeck is that while he does not level up, the EXP he still collects can be distributed to other characters and thus it is never wasted. Even better, since Diek stays at LV1, he always receives the full amount of enemy EXP plus any bonus for battling a higher level foe.
The EXP is also granted all the multipliers if the receiving character has the King's Image and/or the Silk Belt equipped!
I was looking into some game mechanics and found my old note on how killing Serpents and Leviathans in Tukae Cave with Diekbeck should be the fastest way to collect EXP for him outside of other methods like using the Arc Arena in general to kill high LV enemies.
Is it?
I guess not? There are not that many convenient battles at the end of the game and hardly before that, that could stockpile EXP for him so that is why Tukae Cave seemed like the best one all this time to me. It looked like the best scenario available when Diek's survivability and the EXP gain were concerned. He could enter the relevant room in the cave, kill the dragons relatively quickly and survive while being able to heal and also suck out MP as needed.
Then this location occurred to me: Fels Highland.
Select Diek. Go in. Use Divide for instant kills and full heal, and Rob Mind to suck out MP every or every other battle. Takes less time than the Tukae Cave battle, it is less risky too and with a more methodical approach.
One Tukae Cave battle gives Diek around 125-128k EXP. One Fels Highland battle grants him around 80-83k EXP. By the time you do one TC round, you can do 2-3 FH rounds.
Note about Divide:
Underrated magic which can insta-kill anything provided it is used by a character with high enough MAG compared to the enemy's while absorbing all the damage as healing and then optionally divides the heal to characters around the caster.
If the user's MAG is 4 times or higher the target's, Divide drains 4/4 of their HP. If the user's MAG is 3 times the target's or higher (until 4 times), Divide drains 3/4 of their HP and so on. Rob Mind works on a similar principle but for MP. This works on any enemy; however, practically it is impossible to kill stronger enemies with higher MAG or even a maxed out character would not achieve such a value. Still, it can be powerful when used by high MAG characters or monsters even if it drains half of the HP.