V20 or V5 for a Gangster-Age Game?

I'm building up an idea for a game I'd like to run, set in the Jazz Age - late twenties/early thirties America, with big suits, big hats, big attitudes, and so many films noir that you don't know your Humphrey from your Darin.

My question is, would V20 or V5 be better for building this sort of game mechanically? The dense worldbuilding of V20 might make balancing difficult, but V5 is a game I'm less familiar with, and is built more deliberately around the modern era with all the emphasis on the broken Masquerade and the Second Inquisition.