I don't see any difference between "main" and "secondary" weapons: both classes are used to shoot other ships. More meaningful distinctions include:
- Weapons that can be mounted arbitrarily vs weapons that require a special position (e.g. gigantic particle accelerators along the middle of the hull of a large and elongated ship)
- Weapons that can be aimed autonomously (e.g. typical real-world artillery) vs weapons that require orienting the ship to aim (e.g. said particle accelerators, and launch tubes for missiles and torpedoes)
- Dumbfire vs aimed projectiles.
What's available in these different categories and effectiveness of different attack types depend on the needs of your game. For example, the first post shows a bias towards relatively low power and not very fancy weapons (only very large guns against very weak targets are capable of serious overkill, while humble weapons that don't pose a threat to well armored targets are common), accompanied by an expectation of weapons hitting almost always (no dodging or evasion) and, as a consequence, of battles of attrition being decided by imperviousness to damage. It would be appropriate for good armor to be very heavy and bad for maneuvering, to make heavy ships pay for it, but very effective against weak weapons, and for good energy weapons to require so much energy that they can only be used sparingly, with complications like charging times, turning off engines etc.
Even within these parameters, many possible styles of space combat are possible: fleets could routinely ambush each other from good cloaking, hyperspace etc. (making weapon ranges irrelevant), with mere seconds or minutes of engagement as the weaker party frantically escapes with FTL drives or the like, or battles could last for days as fleets chase each other at nearly the same speed, just out of weapon range, or fast ships with long-range weapons could surround and grind down an enemy without fear of retribution.