1. The dimensions in Cylinder3D are given by the STL file, so if you ant to change it you need to draw a new geometry in some CAD software or you need to create a new geometry using Indicators like in cylinder2d.
2. Please use that one: setNewSlipBoundary(SuperLattice& sLattice,
SuperGeometry& superGeometry,
int material);
It is designed for GPU.