Wave Energy Converter (WEC) technology development while showing promise has not yet achieved commercial maturity. In order to reduce the Levelised Cost of Energy (LCOE) to a competitive level the combination of survivability availability performance and affordability of a WEC has to be optimised. Hence developing an understanding of the impact of key geometrical parameters not only on performance but also on loads is essential. A parameter mapping investigation for an Oscillating Wave Surge Converter based on numerical modelling and small scale tank tests and considering all four key LCOE metrics will be presented.