[TimPC]

If you're joining 3 months into what's often a 7+-year mission (where if you're successful you'll be underpaid for a long-time and make your money on stock) and you expect a 90-10 distribution of shares you better be getting something like a salary (co-founder in name only). These kind of distributions are part of why yCombinator discourages unequal co-founder distributions. You're asking for the company to implode over co-founder issues if you think your 3 months at the start is worth a 90-10 distribution in shares especially when as a non-technical founder hiring a technical co-founder the technical co-founder generally has bigger opportunity costs financially.