>>54075658Big Mag seems tough since it doesn't work with any major energy acceleration in standard, at least in expanded you have metal saucer. Once we get a special metal energy you can try running it in Lugia though.
For now I guess your best bet is an Arceus build with V-guard and DTE, but even then you're only hitting for 200-220 damage.
You could also try it in Magnezone-Dialga as an alt attacker, but the deck needs a lot of basic energy already, so with the special energies on top you'll end up with a lot of dead air in your 60.
Another possibility would be to run it in Ratticate-Clodsire and use the first attack to finish off mons you couldn't poison. Just put a bravery charm on it and pray it doesn't get ohko'd.
Small Mag can use DTE + Raihan to be fully powered up in 1 turn. Exp share can also get the metal energy while filling the tool requirement. At that point you'll want to bank on the opponent being confused, so with stuff like Spidops ex and calamitous wasteland to prevent retreat while you keep punching with Mag. But here too, it's not looking particularly good.
Honestly, I'd just try Mag-V in expanded instead, pic related put up some results back when saucer was in standard.