You can also buy a hotplate used as a 16ohm dummy load, run the torpedo at 16 ohms if and only if it allows other devices to run in parallel with it and the torpedo has an adjustable load parameter, and then this will share the load of the output on an 8 ...
the correct way to do this would be to put a second 8 ohm load in series (simply done with a custom speaker cable) and set the amp to 16 ohms.
That being said, generally super high gain amps like Herberts and Ubershalls have the extra power so that the amp can have the lightening fast attack and release required for certain styles of music. Unlike a vintage Marshall, Trainwreck etc. they don't need to be dimed to sound their best and in fact, have a sweet spot that's well below full power. In most cases, the results will be just fine running a Torpedo with proper unobstructed ventillation without any extra consideration (ie a second load).
The Torpedo will give the best result using a typical setting you might use with a 4x12 attached and there is no "interference" (bar owner, parent, keyboardist, police...etc etc

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Andy