Originally Posted by RacerX
I would say defence takes more hits than HP, but defence doesnt cover you when you are being specialed. If you really need to test the difference you can level a unit to around OC5 and put all custom points in HP to see how many hits you before dying (can ask a friend to shoot u in a 1v1 match). Then restat to Full Def and see if you can take any extra amounts of hits. I am also not sure about the modifiers and calculation steps taken when hit by a different type unit as well.
You can do the same for specials too and find the difference between adding HP or Def. My best guess though is that even if you go full HP it is still very likely you'll get close to OHKO by nukers with points in spec/spec parts.
Been meaning to try it across S/A/B ranks, but I never seem to find anyone who goes full HP in OC, hard to find any experimental piggies.
Who needs experimental piggies when you can do it yourself