If "Options / Space Units" is already set to Architectural, then you only need to change the "Format" in Dimensions to "Fractional"; maybe set up a Preset style for this in Dimensions. If Alternate Dimensions are available, maybe set up a Preset with both types of dimensions. Use "\P" (backslash, capital P) in the Suffix field to stack 'em.
Designer, Deluxe, (Professional, Expert, Basic), Platinum
Windows 10 Pro (1803), 64-bit