"Use it in the power supply section of the one box? I already have the Auricap tweak inside. Is this too small for direct AC current? Where exactly do I hook it up in this case (+ to - of the transformer or somewhere else)? Is it overkill here?"
Use it on the 5 or 3.3 volt DC rail of the one box power supply, which is probably a SMPS, and can use all the help you can give it.
Use it on the 5 or 3.3 volt DC rail of the one box power supply, which is probably a SMPS, and can use all the help you can give it.