After a lot of deliberation and baking around 100 times, I decided to bake the capital of the column to alpha. While this looks a little flat, it allows me to have a much more interesting shape capital without thousands of polys. I am not 100% happy with the result, but when you view it in context I think it will look just fine.
I quickly applied a marble material in Substance Painter, but I intend on doing a full pass of all the marble materials at the end, to ensure consistency. As this scene is predominantly made of marble I think it is important for there to be a consistancy between them.