Thanks but two more
How does allegiance work across star systems does it still use distance from home or is it always 25%?
Allegiance is determined by how many phase lines are between your homeworld and the target planet. If your homeworld happens to be close to the star, your other planets in other star systems close to their star will have slightly higher allegiance. I think.
If there are 6+ jumps between your HW and the planet though, the planet can only have an allegiance of 25% (max 35% with culture).
When wiping a player out should i colonize his worlds or rush to the capital?
Well, you're playing AI, right?
Generally you've won the game once you've wiped out the enemy's fleet, at which point the AI will either surrender or you'll be able to advance and wipe out everything at will.
But when you fight further in enemy territory, you'll generally take more losses, and it'll take more time to replace your units. So except in unusual circumstances, usually you should aim to fight on one of the enemy's front line worlds if you're attacking.
If you have more cash than you need (which is often the case in the late-game when playing AIs), colonizing the enemy's dead worlds is often a good idea which can help if you want to move frigate factories or repair structures up.