I tested in single missions and now I'm running a campaign with a Sugarboat to test the Mk 10's. Unfortunately I mostly sail in the Solomons, one of the only places in stock campaign where traffic is darned sparse
I would be careful with using auto-targeting. From what I recall, for example, in SHIII every auto-targeted torpedo resulted in a 'critical hit'. It may likewise have side effects on torpedo effectiveness in SHIV.