This paper presents an experimental study that uses many sim-tube displacements to characterize the effect of hydrocarbon solvent composition on miscibility development. It was found that the minimum enrichment requirement can be estimated reliably with a previously proposed pseudocritical temperature, T-pc, concept. Tuning equation-of-state (EOS) parameters to match these results required incorporating rate and recoveries from selected slim-tube displacement tests in addition to conventional PVT data.