Please give some guidance, experts, regarding the thermocouples on the surface of the furnace tubes

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The furnaces in our facility use coil-type radiant section tubes. However, the specifications provided by the design institute state that the tip of the thermocouple on the surface of these tubes should be in a position away from the flame, with no direct contact with it. Yet, feedback from the equipment team suggests that the tip of the thermocouple should be welded in a position directly facing the flame (without direct contact). Is this approach reasonable, experts? Could it affect the lifespan of the thermocouples? By the way, the thermocouples arrive in a length with some clearance; when they are installed in the flanges, due to the high-temperature resistance and hardness of the protective tube material, there is little space between the pipe and the furnace wall, making it difficult to bend the pipe (the protective tube should be installed in a position away from the flame). How do the technicians solve this problem? Thank you! ! !