electronfusion
Yamadori
@Cadillactaste and @Brian Van Fleet your ideas sound the best if trying to create a showable specimen as soon as possible. But if the rest of those branches were left on for now as sacrifice branches, I imagine they would help thicken those exposed roots faster. I'm just thinking in terms of my very limited experience with flowering quince (including one smaller toyo nishiki), which is 3 years of happy flowering and lots of leaves, but hardly any thickening. It seems like anything you could do to thicken it up now would be helpful to its aesthetic in the long term.