Many previous investigations of IET-driven-mixing use a fixed IET, i.e., an IET that reuses the same cut locations and permutation for each iteration . Fixed IETs can mix slowly if designed such that the IET is aperiodic with some conditions on the "rationality" of the map. However, to increase the efficiency of mixing, Smith et al. outline a sequence of variable IETs, where cut locations (as well as the permutation, although the permutation is fixed in this paper) are free to vary with each iteration. The ad hoc method described by Smith et al., is the basis of the longest segment (LS) method implemented here. The LS method, when applied to an initially fully segregated domain, can be shown to result in the most frequently optimal mixed states with repeated application, as shown later.