Actually I wasn't intending to use these sets, they were just examples, that's the reason of the neutral nature (simpler calculations). And I just thought that I was not very clear, as my question regards more stat / damage calculation than Effort points.
And, as you said, HP would be better than defences for Shuckle because of its very low base HP, but for Wigglytuff, for example, it would be the opposite, right? So I suppose the best way to boost the resistance on a pokémon is to conciliate proportionally its stats depending on the case?
I always tought that 1 more point of HP will make the pokémon more resistant in both sides, but not as much as 2 points, one in each defence, is this right? But I also see most of the sets of bulky attackers prioritizing HP over defences, why would this be?