It is interesting that by my eye judgement, the handle is 1/3 of the overall length, which means it is 1/2 of the blade's lenght.
In a purely functional perspective, I have always thought that the golden proportions for a sword would always be 1/3 handle + 2/3 blade.
It just works in very harmonious balance and the Thais knew that.
Some of my own examples just to corroborate:
Apologies for the bandwith.
Thanks once more.