In my experience, angel investors bring money but little else. There are exceptions (super angels, etc.), but most angels expect you to run the business, have the ideas, turn them into something profitable and figure out how to make it all work.

If your investor has specific expertise in your market, it makes sense for you to try to tap that expertise. Is once a month good enough? If I had an angel investor with specific expertise in my market, I'd be asking the investor how much time they are able to devote. I would take as much of their time as they could devote - so the answer is really with your investor.

I'd be happy to get on a call to discuss your specific situation.