There's already at least one great Lucy/Kaede LoRA but it had a distinct lack of helmet Lucy. I tried to recreate the design using 1080p screengrabs, and a few choice fanart pieces depicting it.

Works reasonably well in most cases, though the part that often suffers is the part over her mouth (the inset triangular segments). Overall though, it came out pretty damn good.

Works well at most CFGs below 8, can produce non-distorted results up to around 10, but resembles the original helmet a lot less.

Plays very nice with PonyRealism, if you prefer a semi-realistic look.