I think you are looking for the system variable DimFrac. When using architectural or fractional units, setting DimFrac to 0 is horizontal, 1 is diagonal and 2 is not stacked. On the command line type DimFrac and then your choice. You can type DimLUnits and change it to 1 fo r scientific, 2 for decimal, 3 for engineering, 4 for architectural, 5 for fractional and 6 for Windows Desktop default. You can make buttons or simple commands to change them. I use UA to change to Architectural not stacked and UD to change to Decimal.