The January transfer window may still be a mere speck on the horizon but, for Rangers’ recruitment chief Nils Koppen, fail to prepare means you better start preparing to fail. The former PSV Eindhoven and KRC Genk scout is already putting plans in place for future transfer windows at Ibrox. And if Nils Koppen’s first summer at Rangers is anything to go by, expect the Ibrox giants to scour the market for left-field additions and bargain buys. Koppen used his Eredivisie experience to bring in Robin Propper, Vaclav Cerny and Neraysho Kasanwirjo before August’s transfer deadline. Rangers also sign…