Chansey test
Powered a chansey to 1200 and something(lvl30ish), put it in a gym. Attacked it with a 2700 gyarados with no dodging. Had about 20 seconds left.
Not the tank a few claimed it would be on other sites but very very formidable and annoying. If I was in a hurry and saw a chanseyed up gym I would not mess with it. I would rather fight a snorlax. Would be good to stack or put on top of dittos(since people are showing those off at the moment).
Just thought I would share if anyone was interested like I was.
Answers
Probably depends on the distribution of IVs within the 3: The higher the key base stat, the less difference (% wise) IVs make. So on Chansey, which has enormous stamina (HP) as its key stat, a worse than average stamina IV will have little overall impact on tanking power, but a 15 versus 0 on the attack stat is going to have a bigger impact on CP. I guess nobody is going to expect Chansey to actually beat anything though, so I'd probably go for whichever one has the higher defense & stamina stats. And I guess moves don't matter if you evolve to a Blissey once gen II released....