I rebuilt the brakes on the Valiant wagon to be 10" drums back in the 90's, but have since reserved a set of KH discs for it... Now I have to decide if I want to remove the brand new front 10" drums and replace them right away, or run them for a while and then convert to disc later...
I'd run them unless there is some issue. If you can't get decent linings Firmfeel carries a semi-metalic lined shoes, Porterfield and Rochester Brake will reline and arc.