I can only account for Levels 1-4 as that is all we have. Once we have full levels and multiclass this build goes out the window.
I assume you referring to the fact that twin spell requires you to choose a second target - which wouldn't have Hex. Fair point.
I myself am critical of this build because I think its a lot of work for a minor payoff, but sort of a funny synergy.
That's fair,
For Twin spell, though, as well as it being necessarily two targets, it also requires that the spell being twinned is *incapable* of targeting more than one creature at the level at which you cast it - not just that you 'do' target only one creature (as with war caster's reaction cast), but literally that the spell cannot be made to do otherwise, so sadly Scorching Ray (which does have excellent hex synergy) is never appropriate for Twin.
As a general rule of thumb, if there's ever an ability or class perk that mirrors another one, or two that are similar in nature, and one is stronger than the other, and you can't recall which version is the one that Sorcerers get... it's the weaker, more limited or less useful one. Always. We get the shaft every time.