Thanks for the input. Aim for 45 deg makes sense.
For the curious, we have underground parking at our apartment with abrupt changes of grade to get from the street over the gutter up over the sidewalk and down the ramp. Before buying the C8 I wanted to be sure I could park in the building. Your iPhone likely has an Inclinometer App installed, so there is no hardship to measure the grades with it and add them to get total grade angle delta. We know the distance between front and back the wheels and the ground clearance is 5.3". It is not beyond the whit of man to figure out what the max. grade angle delta is without a bottom strike and compare to the actual grade angle delta in advance of trying it.