On comparable paper whites; there are measurements of developed silver halide prints in SpectrumViz too for the Ilford (Harman manufactured) analogue B&W papers. Check them against the Harman and Harman by HM, Fiber and Baryta papers. That does not tell much about the way the ink is absorbed but gives a good starting point for the whites.
An extra print run with Gloss Enhancer or a good protection spray can improve the absorbed ink impression.
Met vriendelijke groet, Ernst
December 2014 update, 700+ inkjet media white spectral plots