We report on a design strategy for a Tm,Ho:YLF laser transmitter capable of 125 mJ pulse energy at 30 Hz. Using the results of simulations and experiments, total efficiencies were compared for two different configurations. One is the oscillator operating at 193 K, and the other is the master oscillator and power amplifier operating at 233 K. In the latter case, an extensive cooling system is not required, while the laser efficiency becomes lower. Numerical simulations were performed by using a simple rate equation model. In order to validate the results of simulations, the laser experiments were made with a conductively cooled, side-pumped Tm,Ho:YLF laser in the temperature range of 195-228 K. Based on these results, an optimum configuration to achieve the 125-mJ pulse energy are discussed.