I don't need a theory to decide I'm unwilling to sign up for more than N personal inconvenience; I can observe it as an experimental result.

it sounds like either the theory is quite incomplete, or your limit of N is counter to your moral beliefs

Yes, both of those seem fairly likely.

It sounds like you're suggesting that only a complete moral theory serves any purpose, and that I am in reality internally consistent... have I understood you correctly? If so, can you say more about why you believe those things?