BlackJaguar: Yes, you are right, I need to adjust my approach. I get Oda down to about 40x percent health, and then he activates camouflage and fully regenerates...
This is where you need to find him, ASAP!
Disclaimer: My knowledge of this encounter is outdated (patch 1.52, Very Hard difficulty), but unless his abilities has been radically changed in 1.6 / 2.0, this is what you need to do:
If you can manage to track him while he's camouflaged, and attack him while he's standing still, you will interrupt his regeneration. And I've found he likes to hide in the container with the flare, so fighting him away from this location, you can pretty much predict where he'll go to regenerate.
You only have seconds, so here you literally need to shoot at shadows to stop him. I find an assault rifle to be the best here, as you only need to land a couple shots to cancel his renegeration.
Once interrupted, he will charge you, so get ready to jump back and out of his way.
EDIT:
I am currently at this mission in my current (2.0) playthrough, but I've been too busy in Dogtown (and done the fight with Oda many times already), I've deliberately postponed it this time. I can go ahead and do it if you'd like some updated information.
I have been..."editing" my weapons (800 round magazine Defender, 1300 Damage Ashura, 400 damage Lizzie etc.), but for the sake of realism, I'm willing to take him on with the regular weapons.
My current character is focused on hacking and handguns - or at least I was, before the 2.0 release.