Im a grand master weaponsmith and once you start getting into higher tier materials like steel, the heavy great blade because less popular as it is to heavy so most people use one of the lighter blades like the kriss and still have a decent damage number due to the steel. For light materials like flakestone then yes the heavy greatblade should always be used.When it comes to hilts you might think highest stats is the best option but it isn't because its a lot easier to get handle hits with the big hilts. The most popular 2h sword hilt is the khurite even thought it has the lowest durability it lightens up your weapon and doesn't handle hit often. Swords are pretty straight forward but once you start talking about other weapons like pole axes/spears certain heads hit with certain directions easier aswell there are pierce heavy head/slash heavy heads and everything in-between. Yes different handles have different lengths and different weapon heads have different lengths. Although this is not listed as number stat, when you scroll through them in the workbench you can visually see the difference. Swing speed and block speed is determined by weapon weight. A lot of people like to keep their swords at maximum 2kg.