I have a simple VGC question for y'all:
If my Amoongus for instance, uses Rage Powder, and the opposing pokemon uses Hyper Voice or Rock Slide, would that sort of attack still hit both pokemon? Or would it all get re-directed to Amoongus, ignoring the team-mate?
Spead moves will hit both Amoonguss and its partner - this is the most common way to destroy redirection setups. SubDD Mence + Amoonguss for example: you can spam Pixilate Hyper Voice and fubar the whole setup. Does nothing to Amoonguss, sure, but Amoonguss is accomplishing even less. Also, there's a SQSR thread in the VGC section too. :P
I think it's fair to say that, since Bastidon's base SpA is lower than base Atk, it'll be unlikely that anyone runs a special attacking variant. In fact, Bastidon has a great special attack move-pool, but a 47 base stat and the lack of an ability such as Sheer Force makes this a discouraged option for Bastidon. I'd be surprised if anyone runs more than one attacking move at all.
Therefore you can go 31/31/31/x/31/0 for the ultimate slow pokemon, or if you want to leave that SpA option open, 31/31/31/31/31/x since speed doesn't really matterl
It never does run more than 1 attack, if any, but on its only "offensive" set it actually does run special moves + Metal Sound. Even with its horrendous Sp. Atk, just about anything looks scary when you're at -2 Sp. Def and can hit SE. Rock/Ground/Ice/Electric/Fire coverage isn't bad at all (and it has Flash Cannon I guess). Physical has Screech and Curse, but only has Rock/Ground/Steel coverage by comparison. Both offensive stats are absolute trash, so imo you may as well go with Sp. Atk since it's unaffected by Intimidate, Burn, and has more coverage options.
But really, Bastiodon shouldn't be attacking. It should just use its adorable face-shield.
I actually happen to have a Sassy 31/x/31/31/31/0 Bastiodon. :3