Both the 24" Type 93 M1 and 24" Type 93 M3 launchers are useable - they just run different variants of the same torpedoes. The M3 torpedoes have only 3/4 the range as their M1 counterparts, but almost 1.6 times the firepower. The M1 torpedoes don't hit as hard, but have insane range. Actual choice between both launcher and torpedo sub-type is mostly a personal preference.
The Type 93 M1 Mod-1 torps have the longest range of any torp in the game, and often go past enemy BB lines to even hit CVs. But they don't hit hard. They're most useful in HA and larger GBs with numerous smaller ships. The M3 Mod 1 are still solid in both HA and GB, but you'll be trading number of hits for damage per hit.
The Type 93 M1 Mod-2 are fast (second fastest in the game) short-range weapons for blitz, but there's little reason to not just use the more powerful M3 version there - the Type 93 M3 Mod-2 is the second most powerful surface ship torpedo in the game, and still tied for second fastest.
The Type 93 M1 Mod-3 have just high enough range to make it from one BB line to the other, and these torpedoes hit HARD. However, they are painfully slow and thus easy to outrun or dodge. The M3 Mod-3 require running into harm's way to effectively reach enemy BB lines, and still have the speed issue, but they're the most powerful surface torp by a wide margin - to the extent that they actually rival weaker SS torps! In short, you won't get many hits, but the ones you do get will be big ones.
