Arcane/Fire build

My understanding is that arcane mages typically cycle 3-4 arcane blasts into a frostbolt/fireball until the debuff wears off, and repeat. Most builds I've seen use frostbolt as filler, presumably in a 40/0/21 spec, but I've heard mention of fireball instead. My question is whether a 40/18/3 build would work with a similar rotation. Essentially I would just be fireballing and keeping up improved scorch during these cooling down periods, since scorch is a mana-efficient move. Is this viable with sufficient (T5/6) gear? I'm not terribly concerned if it's a small personal dps loss relative to arcane/frost, given that it would free up any other fire mages to fireball spam. Mostly I'm curious about whether it would be a significant dps loss, and if it would be sustainable in longer fights.

The general build in question:
https://calculators.iradei.eu/talent...00000000000000

Pyroblast because of its synergy with PoM.

Thanks.