Do two concentration spells at once? Seems suspect, happy if true, but I definitely need to try it for myself.
Sorcs are simply broken due to metamagics, so yes twinned spell lets you use two single target concentration spells, but the trade off being you can't use wall of fire / cloudkill at the same time.
Heighten gives them the highest DCs for the hold spells, quicken lets them cast two spells per round.
So yes its based on 5e rules, but its stupidly OP compared to all other casters, you just don't get very many spells. Also I realized if I save scum blink rolls I don't need shield at all and it no longer even works much so hmmmm.
Swap shield for haste.
