I prefer +health since if the puppet is destroyed, Kankuro damage is non existent.

if Kankuro is your main damage deal, they will try to seal or interrupt on turn 2. Plus enemies with an aoe can kill puppet relatively easily if it has low health. Its just my opinion how to use Great war kankuro, I'm earth so I prefer a long drawn out battle rather then a short one with great rasegan finishing off kankuro or vice versa.

correct, dot damage is based on enemy health.

The other poster doesn't have great war Kankuro or is just trolling. Good luck using wind, I used to be wind until class change. The other way I'd switch back is if I manage to get both kazekage gaara and conference temari. Wind growth stats on defense and health and so low, most players in my server can kill me in one or 2 rounds.