This is just a suggestion sketch that shows how to improve the readability of the text when using the splendidly improved Inkscape’s measurement tool by Felipe Sanches. In both cases the white outline is removed. The white outline introduces way too much visual contrast and distorts the shapes of the glyphs, lowering the readability in the process. The suggested improvement introduces a semi-transparent rectangle background whose purpose is just to provide a clean space for the textual information.
You can find a lot of common world examples for this kind of cleaning up of the area from other visual noise in order to display important info. Car license plates, various traffic signs, various nutritional, warning, specification info, etc.
In these examples, black and white are used for the text background since they blend nicely over any colors behind them, but I can imagine that some other colors could be used as well.