In magnetic or inertial fusion reactors, hydrogen, its isotopes, and lithium are used as fusion fueling materials. Lithium is considered a fusion fuel and not an impurity in fusion reactors as it can be used to produce fusion energy and breed fusion products. Lithium hydride and lithium deuteride may serve as good ablating sleeves for plasma formation in an ablation-dominated electrothermal plasma source to propel fusion pellets. Previous studies have shown that pellet exit velocities greater than 3 km/s are possible using low-z propellant materials. In this work, a comprehensive study of solid lithium hydride and deuteride as a pellet propellant is conducted using the ETFLOW code. Relationships between propellants, source and barrel geometry, pellet volume and aspect ratio, and pellet velocity are determined for pellets ranging in volume from 1 to 100 mm3.