Then, what gear would you use on account 1's demon machine sorc?
Aha! I see. Now this is a rabbit hole! Much of the gear would stay the same and you'll adjust to how and what you play. The biggest difference would be your charms, as you'd have no need to clog up space with fire skillers. Think in terms of @res, life, fhr, mf, etc. This would allow more swaps.
If you're ok teleporting/static on switch, this hits 105% FCR:
Armor - Viper with RBF
Swap Weapon - Hoto or even Wiz
Swap Shield - Spirit
If stacking FHR with charms, it could also open up the gloves slot for FCR gloves (Magefists, Trangs) + Viper + 2/15 ammy to hit your 63% on main. Helm would still be FF for the -15, belt razortail, boots are your preference, rings to plug holes that charms can't for whichever area you're running (i.e., CBF, absorbs, etc.)
That's half the fun with this build, is there's no one best method, and you can choose-your-own-adventure to suit your preferences. Think of it like gear swapping in PvP to maximize whatever you're running.