Snorlax or Raikou

Raikou for sure

An 86 versus a 90ish won’t make much of a difference as a defender. However with Raikou being the best Electric type in the game, a decent generalist and only one weakness, it will be a better choice to get. You want a good IV Raikou over a good IV Snorlax.

Raikou, the best electric attacker out, thought elecavire and magnazone may change that.
defense isnt that major of a think, and snorlax is an ok defender, but in a gym of all fighting weak pokemon, its nothing but fuel for machamp, off type pokemon can do its job better

Find someone else around you with low-IV Bodyslam Snorlax and trade them to get a re-roll.

I would say go for Raikou cause the chance of getting a Snorlax above 90% is slim, it's up to you though if you want one more chance at it. The best one I managed to get was an 89%.

You could choose the Pokémon you like better. If that's Snorlax, then even if you don't get the IVs you want you'll have more candies to feed to a monster you like. I think something gets lost when we start looking at monsters and seeing only a set of stats and a few variables.

Then there's the fact that aside from having the Fighting muscle to uproot high-CP Blisseys, almost nothing actually matters in the gym game. (The other exception is shaving raids down to the smallest possible teams. If that's your thing, cool.) I do most of my attacking and defending with garbage evolutions. It's fine.

Raikou