Roman Numerals
Change integers to Roman numerals in any output expression.
In a clock gauge.
In[1]:=

clock = ClockGauge[{10, 10, 30},
TicksStyle -> ColorData[40, 2], GaugeMarkers -> "FlatProfileNeedle"]
Out[1]=

In[2]:=

clock /. Text[s_Integer, rest__] :> Text[RomanNumeral[s], rest]
Out[2]=

In an angular gauge.
In[3]:=

AngularGauge[
Quantity[714, "RomanOunces"], {Quantity[0, "RomanOunces"],
Quantity[1000, "RomanOunces"]}, GaugeLabels -> "Unit",
PlotTheme -> "Monochrome"] /.
Text[s_Integer, rest__] :> Text[RomanNumeral[s], rest]
Out[3]=
