Making small ships more valuable

I would like to get some feedback and input on a rather simple idea to make smaller ships useful until the end of the game. The idea is to

a) modify the torpedo weapons (anti-matter, quantum) in the game as well as
b) the attack and defense characteristics of smaller ship types compared to the big ones

to correspond to the "real-life" situation in naval warfare in the beginning of the 20th century.

Around 1900, the big capital ships became increasingly threatened by small, agile and relatively cheap torpedo boats. While a hit from a capital ship could blow a torpedo boat out of the water, the small ships were very difficult to hit by the large, unmanouverable behemoths. If the torpedo boats succeeded in approaching the capital ship sufficiently to be in their (short) torpedo range, they could fire their load. Compared to their size, torpedos deal an awful lot of damage (also because they hit beneath the surface), so the damage potential/kt relation of a torpedo boat is relatively high. The relative cheapness of torpedo boats added to this: for the price of one battleship, dozens of torpedo boats could be built. Smaller, more agile ships could dodge the rather slow torpedos, but for a capital ship, this was difficult. Therefore, the torpedo boats had to be intercepted before they got in range. Firstly, capital ships had to also carry additional smaller, more dynamic weaponry. More importantly, they had to be protected by screening vehicles which were themselves small, agile and more expendable. This was the birth of the destroyer.

In the game this situation could be mirrored by

a)strongly increasing the damage and decreasing the range of torpedos. In addition, one might give them a minus on attack so that they are only fully effective against large ships (which themselves should have a larger minus on defense values)
b) giving smaller ships a considerable defense bonus (and/or larger ships an attack minus)

This way, small ships would remain useful until the end of the game. It would also not make large ships obsolete. The bigger guns and heavy armor would still dominate the smaller ships with standard weapons. In turn, the smaller ships with standard weapons (i.e. without an attack minus) would dominate the torpedo boats because of theri higher range and the attack minus of the torpedos. It would be a kind of "rock-paper-scissors" situation - as it was in real life.

All the above can be relatively easily modded in the data files. However, I am not sure what kind of modification would be necessary for the AI to use torpedo boats and anti-torpedo screens. Will it do so automatically? Do I have to introduce a special ship class "torpedo boat" and tell the AI to build it (is this done in a text file or in the AI scripts?) ? If it builds torpedo boats, can I tell it to use them in an effective way, i.e. in "hit-and-run" attacks on capital ships, not against smaller units? Any other thoughts?