A straight forward, low tech method for measuring base bevels is to use feeler gauges or other objects of known thicknesses (0.5mm, 0.7mm, 1.0mm, etc).
The direct ratio between typical bevel angles, is the metric height (mm) of the angle, at the accepted distance and easy to remember distance of 60 mm/6cm from the edge (actually 57.3mm).
The SVST WC Tru Bar has an engraved line at this location to facilitate easy and quick base bevel measurements. Any true bar can be marked at this location and used to measure the base bevel angle by measuring the height above the base when the bar is parallel to the edge.
If a feeler gauge isn’t handy, a typical credit card measures 0.8mm and 1.25mm at the raised lettering.