What are the apparent visual magnitudes of Spica A and Spica B?
The Wikipedia article says that Spica A has 8 times the luminosity of Spica B (presumably that's at maximum.)  Magnitude is -2.5*log10(I/I0). So if the combined magnitude is 0.97, the magnitude of component A is ~1.1 and the magnitude of component B is ~3.3.