A general rule of thumb is that you will will need the turning stage in the crystal for being 10°C higher compared to the higher operating temperature in the OCXO oscillator circuit. Electric power Dissipation: TCXOs show increased electrical power dissipation than common oscillators because of the additional circuitry needed. https://cashshvkx.ourcodeblog.com/31134278/top-guidelines-of-tcxo-oscillators