A well known challenge in nanotube research is that typical SWCNT samples contain a wide range of diameters, roll-up angles, metallicities, lengths, and defect states. This structural heterogeneity leads to complex superpositions of spectral features and complicates efforts to determine fundamental and useful properties such as absorption cross sections of specific (n,m) species. We report here 11 new absolute E₁₁ cross section values measured with our recently developed method of variance spectroscopy. This method analyzes the minor variations in fluorescence spectra captured from different small regions of dilute bulk samples. These variations reflect random changes in local compositions resulting from the limited number of nanoparticles within each probed volume. The variations among a set of ca. 2000 independent spectra are analyzed at each emission wavelength to provide spectrally resolved information, in contrast to familiar fluorescence fluctuation techniques such as FCS. This analysis let us obtain the particle concentrations of specific (n,m) species within a sample. Through combined variance and absorption analysis, we have thereby been able to determine the peak and integrated E₁₁ absorption cross sections for the (6,4), (9,1), (8,3), (7,3), (7,5), (7,6), (10,2), (9,4), (8,6), (9,5), and (8,7) species calibrated against our previously reported (6,5) value. These measured cross sections are found to increase substantially with decreasing nanotube diameter and to be systematically larger for mod 1 than for mod 2 structures. We believe that these results will allow absolute, structure-specific SWCNT concentrations to be easily determined in basic and applied nanotube laboratories. In addition, the use of variance spectroscopy provides a promising new tool for extending such fundamental cross section measurements to additional (n,m) species.