Ask HN: How much equity for first tech (Director/CTO) hire?

Hey HN,

I'm considering jumping into a startup under as Director/CTO for a post-revenue, seed-backed (including seed bridge) startup. This would be their first full-time tech hire. They're offering pretty competitive salary but I'm wondering how much equity I should negotiate for. They have an MVP but want someone to come on and actually build a scalable (greenfield) platform in anticipation for a Series A next year.

A bunch of stuff online says from 3-5% typically for a first tech hire, but if I'm going to be building a majority of the platform (notwithstanding a couple senior/junior hires as well), should I negotiate for more?