In dealing with the census on research projects I noticed the two asset valuation categories, but have never really used it for analytical purposes. Rather than looking at the entire populace of a region in the census, or random name samplings from it, you might instead compile a list of specific known Jayhawkers and cross reference those names with their census asset data and see how their numbers fit in with your thesis. Could be the raiders were not political and were merely looking for booty, in which case they might tend to be from a lower socio-economic background; or could be they tended to be abolitionist immigrants from the Northeast, in which case they might tend to be of a more affluent background. I am way beyond my level of expertise here and am just tossing out thoughts. There are probably some type of studies on the subject that have already been done. You might make inquiries on the Kansas board.