weight 0.7 is best.
I created this LoRA as requested.

Please read the description.

outfit1 (purple hair ↔ black hair)
1girl, solo, long hair, purple hair, bangs, black eyes, bright pupils, white pupils, white skin, school uniform, red neckerchief, white shirt, sweater vest, black sweater, short sleeves, pleated skirt, pink skirt

I uploaded a sample image of the outfit as a post.