I don't have the experience or expertise of Kraigwy, but it seems to me that a small, RELIABLE, powerful flashlight is important for your work; i.e., a flashlight using CR123 batteries so it is a good fit in your hand. Although a bright flashlight, e.g., 60 to 200 lumens, does "light up" the whole room, it is also blinding to a person facing it. Since any flashlight will disclose your position to another person in the same room (or possibly in an adjacent room), it seems to me that a small (easy to carry) powerful flashlight is appropriate for your job.
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