Triples was pretty heavily under-explored here, especially competitive pvp speaking, largely because no official format supported it (VGC remained doubles).Question for competitive-ish gen 5: Which rotom form is most helpful for sandstorm triples, or should I not use it at all? I was thinking that wash would be good for both coverage and when weather gets overwritten, mostly by hail or drought. I’ve heard that Heat was also good, and I suppose mow or even fridge could help offensively. Current team consists of definite Excadrill and Garchomp sweepers and Tyranitar setter, with pending support/ walls of Forretress and Gliscor.
At best there might be a thread somewhere in Orange Islands for the Battle Subway which might give you some help if you go digging, but don't expect any recent discussion or help... I can only think of a handful of users that may have ever delved deeper than a cursory level to help you out team-wise.
Theormonning, you're probably best off with Mow or Wash; of what I know of Triples is that mons that can target/protect cross-field and are immune to spread moves are highly valuable, so either will fit in well with your team. That said, Rotom offers neither cross-field targeting with any Flying moves (apart from Air Slash) or something like Aura Sphere, or protection with the likes of Wide Guard, (it is at least Earthquake-immune) so you may be better off with a generic supporter in that regard.