Last year, I gradually acquired the key building blocks of the new transistor PA: locker, transformer, DPS PA 4x MRF150 a Block bandpass filters a military transmitter. The filters are switched relay and dimensioning seems to be sufficient for high performance.
switching will be managed in parallel with the antenna band decoder.
cooling the two-point, the whole construction will be cooled by a fan on the rear panel, heat from power transistors will be done through a copper plate on a large aluminum heatsink. Source will be stabilized, classical design of toroidal transformer.