can we change "threading-model Cull/Draw" in runtime?

in loading time ,we want to use single thread ,and “preload-textures 0” to quickly load models

in run time, we want to use mul thread to get more performance

without “preload-textures 0” mode , we need more 20S to load all models

base.graphicsEngine.setThreadingModel("Cull/Draw")

thanks!!!