Sure open that can-o-worms.
Always glad to
20 missiles in a ton?
Well, at 50 kg each missile we find 20 per ton (as mass and volume are not discriminated in CT). In MT, where they were, each missile was 0.1 kl in volume, so allowing 135 per ton (maybe too much, IMHO)
Storage only or is there a related auto loader?
I guess they could be both. Auto-loader would be tied to a specific weapon (but available for immediate use), and storage to refill auto-loaders after the ehgagement (so that less missiles would be lost with the loss of a turret).
So, your ship could have 1 dton of magazine per turret (giving them 20 more fire rounds) and more missiles in storage (be it in special storage or on the cargo hold) to refill them after the engagement...