can we see 2 units of measurements

You can do this simply by yourself:

Define a 'Master-Unit', let's say mm

Create a small macro which draws – depends what grid you need – maybe each millimeter in Y-Direction

Copy this block for the Y-Direction:

Sub MkRuler()

Dim CurValue As Double, CurDelta As Double

Dim CurLy As Layer

ActiveDocument.Unit = cdrMillimeter

Set CurLy = ActiveLayer

CurDelta = 1

CurValue = 0

Do

   CurLy.CreateLineSegment CurValue, 0, CurValue, ActivePage.SizeHeight

   CurValue = CurValue + CurDelta

Loop Until CurValue > ActivePage.SizeWidth

CurValue = 0

Do

   CurLy.CreateLineSegment 0, CurValue, ActivePage.SizeWidth, CurValue

   CurValue = CurValue + CurDelta

Loop Until CurValue > ActivePage.SizeHeight

End Sub

Create a new layer

Rerun the macro with a step width – also what you think to need – of 1/8 inch (in this case you have to divide 25.4 mm by 8)

CurDelta = 25.4 / 8

Then you have two layers with different grids you can show or hide as you need