Studies of spin-dependent observables generally rely on calculating the difference between scattering yields for opposite spin states of the beam helicity or the target polarization or both. While the beam helicity can be changed at rates of up to many times per second, target polarization flips involve times on the order of hours or longer. To measure observables that depend only on the differences for opposite target polarizations with minimal systematic effects caused by changes in the beam, target, and detector systems, special methods need to be followed. One option is to use targets which have two or more sections in the beam path, each with materials polarized independently. While this approach does not remove all sources of systematic effects, it can be combined with frequent alternation of spin states to improve the control of time dependent and configuration uncertainties.