[wayneyeager]

I would use the spare time (10 hours a week you said) to develop a prototype of your application. MVP, etc. Keep your job, and start out small with your side project.

Work on it until someone will pay you to use it. Over time, improve it, get others to pay, etc. Repeat until you can you reasonably devote yourself to it full-time.

If your app/idea/situation doesn't lend itself to that sort of organic growth, then you've no choice but to roll the dice and go big, or stay where you are. But since rolling the dice sounds unlikely, I'd contort myself and my idea as much as possible to fit into the grow-slowly-as-a-side-project paradigm.

[Source: my experience. This is what I did to launch my first biz. Grew slowly. Company got acquired.]

[rcavezza]

I agree completely with Wayne Yeager.

More than that, I'd probably use some type of landing page technique to help gauge demand for your top 10 ideas. Create simple landing pages with a tool like unbounce to see who will click the signup, download, or buy buttons for each idea and drive targeted traffic with adwords.

This is probably the easiest way to narrow down to your best idea w/ some market validation.