I'm interested in learning about half step gearing. Does anyone ride a bike with such gearing? What are its strengths and weaknesses? How difficult it is to convert a C&V bike to half step?

The reason I'm asking is because my latest purchase - the Raleigh Team Pro - has 53/42 x 13-17 six speed. I want to get a 23 or even a 24 big cog for climbing. I'm riding it on a century in June.

But with just five steps, going from 13 to 23 looks to require much larger steps than I'm currently enjoying. And the resulting ratios look very duplicative. I started playing with different chainring sizes - virtually, using a gearing calculator - to see if I could get less duplication and narrower steps. And it occurred to me that this is, or I think it is, what half step gearing is supposed to do.

So, I'm wondering if it makes sense to convert the bike to half step and it is even possible. Crank is old Super Record and so is the rest of the drivetrain. I'm limited to six speeds, or maaaybe seven.