I'm a novice when it comes to manual, I've only just begun training myself in this. But, perhaps presighting might work? Observe both targets and note their individual values, designate specific tubes for each target before hand and set their depths (I'm sure any descent sub skipper does this anyway). Select your first target, input previously acquired info with updated accuracy, fire, quickly move to next target, and repeat.
I don't know. I'd like to hear what the vets have to say.
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