In terms of performance, shorter blades have much more nimbleness than longer ones but obviously less range. Longer hilts instead give better speed but less accuracy than shorter ones.
As a rule of thumb, your sword can excel only in two of these three values:
Range / Speed / Accuracy
Configuring your weapon in order to find the best proportion according to your style is a core (and fun) part of the game.
Ideally, your sword’s total length shouldn’t exceed the distance between the ground and your armpit.
By tournament standards, the maximum length of a LED Sabre is 125cm.