I mean, does the SubCharge set really need an Eviolite? Why not give it Leftovers? Magneton still has the speed to ensure that Jolly Scizor wouldn't surprise KO, and it can still hit Adamant Dragonite, Adamant Gyarados, Adamant Mamoswine, Gliscor, and bulky Rotom-W first, so it's not completely outclassed by SubCharge Magnezone.
I should probably ask ShakeItUp for his input on Magneton.
Mention in the Scarf set description that Magneton also outruns +1 Adamant Gyarados and Timid Starmie, both mons that Scarf Magnezone cannot outpace.
Under Other Options, you could also mention Hidden Power Grass for Gastrodon / Quagsire, Toxic for Non-Poison Heal Ground-types, Thunder Wave for paralysis, and Metal Sound to beat special walls like Blissey / Chansey, especially with rain-supported Thunder.
You should mention the usual Electric counters in the [Counters] section: Grass-types (Celebi, Virizion), Latias, Chansey / Blissey, Tyranitar. Dugtrio and Magnezone can trap and kill.