Do yourself a favor and create a separate layer called VPorts or Viewports and assign it a color other than white. Then set this layer to "no print" in your Layer Properties Manager. While it will be visible onscreen it will not plot/print when the time comes.
Viewport scales can be assigned in three or four different ways. One method is to activate the viewport then look at the bottom of your screen at the Status Bar. The initial viewport scale will show up as a number. Click on the arrow to the right and a list of standard scales should appear on your screen.
Parametric block? No exactly, but there may be a "dynamic" block. We don't utilize scale bars so I would have to check if one comes with AutoCAD but I do know that dynamic scale bars are available at the AUGI website and possibly at the CADforum website.
I'm Reese. Sergeant Tech-Com, DN38416. Assigned to protect you. You've been targeted for termination.