Share 'Unrobed Ganache'

Hello Folks I am looking to make truffles that do not have a shell (bit like Royce's Nama Choco).  Is it just a case of adding extra sugar - such as corn syrup or inverted sugar - dusting with coco powder and suffering a really short shelf life? We are also considering buying the book 'Fine Chocolates 2 Ganache'  by Jean- Pierre Wybauw.  The book is rather expensive, but we do want to focus on u…