Shulchan Aruch Orach Chaim 487:4 describes a custom to recite Hallel in the synagogue at the end of Arvit on the first (two) night(s) of Pesach.
Some (e.g. Gra) link this custom to the practice found in Tosefta Pesachim 10:5. The Tosefta records that those unable to recite Hallel themselves as part of the Seder, go to the synagogue and hear it read there.
Given that Shulchan Aruch Orach Chaim 472:1 rules that the Seder must only start at nightfall, would the same apply to Hallel in the synagogue? That is, may a congregation praying Arvit before nightfall recite Hallel?
(I'm interested in all answers to this question, whether or not they take into account the Tosefta as a / the reason for the custom of reciting Hallel in the synagogue.)