"Less measure" is only meant to be of significance statistically, not subjectively. For example, if you could exist in one of two ways, one with measure X and one with measure of 0.001X, I would say you should think it more likely you are in the first situation. In other words, I am agreeing (if you are arguing for this) that there should be no subjective difference for the mind in the extreme situation. I just think we should think that that situation corresponds to "less" observers in some way.

My own argument is actually a justification of something a bit like the dust hypothesis in "Permutation City". However, there are some significant differences, so that analogy should not apply too much. I would say that the characters in Greg Egan's novel undergo a huge decrease in measure, which could cause philosophical issues - though it would not feel different after it had happened to you.

I think we should consider this in terms of measure because there are "more ways to find you" in some situations than in others. It is almost like you have more minds in one situation than another - though there are no absolute numbers and really it should be considered in terms of density. If you want to see why I think measure is important, this first article may help: http://www.paul-almond.com/Substrate1.htm.