I would say don't use it. It may be used informally by English speakers, but we tend to use the simple present (e.g. I want) for mental states, emotions or desires.

I think it's probably quite normal anywhere. It's used in a certain case, when you want to talk about being in that moment when something happened. 'I wanted to' is normal but unspecific about the time so that's why 'I was wanting to' became invented, maybe.. so, in certain cases, I think it's totally normal to use it. People also have invented 'I'm not liking this..(similar meaning to enjoying)' etc for the same reason - a specific situation fo bring in that moment, you know?

I agree with Owen. While it may be used informally it's not that common and people still tend to use simpler forms "I want" or "I wanted" instead.

This is normal in Scots and Irish English.