Acrylic does not have the best strength to weight ratio for a sword.
The density and flexibility is a bit on the high side.
Elucidator, Dark Repulsor and Lambent Light all looks roughly 1m in length given your height is in
the 1.60 - 1.70m range.
Other than lambent light, Elucidator and Dark Repulsor looks like one and a half handed sword.
Which is close to Chinese Jian in terms of length sizing,
If you are ~1.65m tall
the blade would be the length from armpit to the tip of the middle finger
(with your arm stretched straight)
with the handle being the length of a palm (from tip of middle finger to the bottom of the palm)
The overall length being 96cm.
The handle would be just sufficiently long to use 2 handed grip
if you size it this way. (which is what seems to be kirito's proportion to the elucidator)
Unless you are planning to use the katana's proportion of 3:1 of total 4 part
blade being 75cm long with 25cm long handle, which is a longer handled design.
that looks kind of oversized handle on the Elucidator and Dark Repulsor.
6 - 8mm is the average thickness of sword blades, meaning
you might ends up with a flappy piece of acrylic.
You could make the blade thicker, but the proportion would be slightly off and might not be as nice if you are particular about details.
The worse thing you would want is the flexing occur near the point of balance on a sword when you swing it,
which could easily snap the entire prop. (lower node of vibration is same spot with point of balance)
Take note while testing out the prop.
This might be fine for steel blades, but for props the vibration could easily destroy the material especially if you choose to hollow out the middle for wire.
Unless you are using the acrylic for non-structural support
on the edges.