When flying a plasma fleet faced with a carrier group, consider using a rolling-delay with your plasma-S torpedoes instead of holding a completed plasma-S torpedo. The power cost per turn is the same (two points per torpedo). While it will require two points of batteries (per tube) to complete and launch as a standard torpedo should you need to do so in mid-turn, it gives you greater flexibility.

If you can end a turn break at a good launch range from enemy fighters, or even the enemy fleet, you can complete the "rolling S torpedo" as a shotgun, allowing you to nail three targets with 20 points each as opposed to one for 30 points. You can also complete the other plasma-S torpedo during Energy Allocation as a standard, enveloped, or even a second shotgun if the situation warrants it - an unpleasant surprise to that enemy fighter group at moderate range.

This is, of course, more effective in the "early war" period where fighters are slower and lack booster packs, but can also be used against ships, especially those who like to "superstack", i.e., put all of their ships in a single hex.