[Alneyan]

20% offence/defence refers to the specific characteristics in the Empire setup. There is also the Berserker culture, giving another +10% offence/defence for cheap.

You should train your fleets to 20%, as fleet training is very easy to do, and does not require the fleet to be actually present at the facility. Instead, you can train your fleet with a single vessel somewhere, and add the actual fleet later on. I guess it is more like "learning proper strategy" than anything else.

You could have been unlucky in that particular battle. It might also be that you do not see all the hits, as weapon fire is usually very fast, and damage does not appear clearly in the screen. If you are really annoyed with your vessels, the Talisman is always a nice buy: it allows all your weapons to never miss their target.

Now that was a nice example of cross-posting if I ever saw one. Neural Combat Nets are amazingly useful, as experienced vessels in the fleet (30% or more) would give their bonus to the whole fleet. You will need to be lucky enough to get one such ship however, as few ships tend to live long enough to score enough kills.