I am planning to replace linear rods with Vslots on X and Z for time being. Are wheels much smoother than rods and are the really precise as advertised? I know most recent chinese printers are using them. Did you go with 3 or 4 wheels per axis. The plan is 3 on Z x2 and 3 on X axis for hot end. I believe 3 wheels is easier to adjust than 4.