[Meta thread] Iron's PokeRole Adventure: The Skull Ruins

[Iron]

It's up to you, of course. And that's a very good theory. But you can also think of it in terms of how long it will take in days: if you do a double battle, you might gain time for an Encounter Slot. Single battle, the gym leader may need to rest a day in between challenges.
Double battles, depending on how often the partners are online, may also take less meatspace time than two single battles.

Then again, gym leaders will only accept a double battle if they have a team that can benefit from it in some way. I need to look into the distribution of spread moves across types. The old "physical" types are likely to have less.

These are all great things for a character or player to be thinking/strategizing about. They're meaningful decisions with no wrong answer.

IIRC, I didn't design any gym leaders who REQUIRE a double/teamwork battle. Those often felt unfair in the games.