Common mass transfer models for multistage distillation show significant deviations between calculated and experimental height equivalent to a theoretical plate (HETP) values for viscous feed mixtures. This is due to a limited transferability of the available data which were mainly obtained from experiments with inviscid mixtures. Separation efficiency measurements at elevated viscosities can be conducted with polymer-enhanced test mixtures and require an alternative plant setup. This contribution addresses the development of an improved plant setup suitable to conduct such separation efficiency measurements. General design considerations, simulative feasibility studies, and plant characterization experiments as well as separation efficiency measurements will be discussed.