Which Raikou to power up?

I always favor attack and defense, because my understanding is stamina only effects the HP of the pokemon, as well as CP. If you have a source that says stamina contributes to energy gain, I would love to read through that.

Taking damage results in energy gain, at a rate of 1 energy per 2 points of HP lost, but the difference in HP between these 2 Raikou is only going to be 2 points, which is unlikely to be the difference in an extra charge move usage.

You're rarely going to be in the situation where you have exactly 50 energy and 1 or 2 HP remaining, plus actually get the charge move off before fainting.

Energy gain from taking damage comparisons are usually done for defenders as they have double the usual HP, and across different Pokemon species, HP or defence IVs don't make a big enough difference in charge move usage.

For example when comparing a high HP but low defence Pokemon to a high defence but low stamina Pokemon, like Vaporeon vs Steelix.

They may have similar survivability but the high HP one will have gained much more energy over the course of battle that it can use more charge moves before fainting.

Back to the question at hand, I'd go with the one that has 15 attack and defence.

If you hit a defence breakpoint against a boss' quick move that damage reduction results in more effective HP than a difference of 3 stamina IV.

Even if it doesn't the defence IV will make a difference against charge moves, and it only needs to make a difference of 2 HP in total fo be just as good as the 15 stamina IV one.

You're right, but the difference is minimal. If one of them already has Wild Charge, then I'd choose that one. Charge TMs are pretty rare now.

I'm not fishing for advice b/c I won't power any of these up for months (might get a better one, too) but three 1900cp 93%
15a/12d/15s TS/WC
15/13/14 TS/TB
15/13/14 VS/TB
I guess the first one is best, since Wild Charge--I dunno, but barely care at the moment

In close cases like these, all things being equal, I usually power up the one which will end up with the highest CP (in this case the second).

But if the other one already came with an optimal moveset and didn't require TMs, I might choose that one instead since they are so close.