Helinski (2024) presents a novel methodology for analysing horizontal paste exposures. This previous study used detailed numerical analysis and field data to better understand the mechanics associated with horizontal paste exposures, culminating in two analytical solutions that capture the controlling mechanisms. The first solution is based on the Voussoir beam theory and provides a method for relating fill strength to overbreak during horizontal exposures. The second is based on Kirsch’s (1898) theory for the stress concentration around a circular opening and provides a minimum strength, below which uncontrolled caving is expected. This paper is focused on the application of this methodology in an underground mine design context and focuses on applying this methodology to optimise the balance between paste strength and dilution. The presented work illustrates that, depending on-site specific dilution and binder costs, as well as the relationship between binder and paste strength, the optimal design methodology could vary from one aimed at assigning very high paste strengths to eliminate dilution, to targeting low strengths, where considerable dilution is allowed. While the solutions proposed by Helinski (2024) offer a useful method for estimating the strength versus dilution relationship, this solution is limited to a plane strain geometry. When compared with the relationship derived from numerical three-dimensional analysis, it becomes clear that the plane strain simplification provides a good representation for narrow stopes but becomes conservative when estimating strength requirements for spans greater than 10 m across strike (ie where the fill spans both across and along strike). This finding also has implications with respect to tight filling. Tight filling reduces the span in an along strike dimension enabling the undercut fill to span in two directions, which provides significant benefits to wider exposure spans. Tight filling is less important for narrow exposure spans.