Don't try to push the issue with arguments about why project-based pricing is better for you. The client doesn't care much about your peace of mind, they want to know how much they'll spend at the end, that's basically it. Insisting just drives people away.
If the client wants hourly, it's time for you to be honest: how long does each thing really take? Because here's a catch that a lot of people ignore - you might think a project will take 10 hours and end up spending 20, then you're really screwed. That's exactly why this client wants control. Before you agree to anything hourly, do a test: time a similar task you've already done, see how long it actually takes, then you know if you can charge a decent rate or if you're going to make peanuts.
My suggestion? Offer a hybrid - propose a quote based on estimated hours, but with a maximum cap. Like: "it's roughly 15 hours estimated, comes out to X value, but I won't go over 18 hours without letting you know". That way the client gets their price ceiling (which is what matters to them) and you get protection against discovering the work is heavier than you thought. If the guy still insists on paying strictly by the hour, then you charge really high, because then you're taking on all the risk. Some clients won't close like that? Just move on, there's more work out there.