Multimeasure rests

Based on the handbook, selecting "Format-style-rests" enables one to select features of the rest bar (min. number of measures, length, thickness, etc) and in "Format-text styles-rests" has a parameter for "multimeasure rest number" but sems to only refer to a range of numbers one can have displayed - the text size (able to be changed at this point) is not the size of the number displayed above the multmeasure "line". I cannot find how to define the font type and size for the number which appears above the multmeasure "line".

Can you please advise how I can set the font details?