A weight of ~1.0 is recommended (You might want to adjust the weight depending on your model). Feel free to experiment with other weights and share your results if you want to!
The main prompt is "Irisviel von Einzbern"
Use "long hair" for her hairstyle.
For her outfits you can try the following prompt: NOTE: Some outfits will work more consistent than others. Casual (Red shirt and white skirt):
"Irisviel von Einzbern, long hair, red shirt, dress shirt, white skirt, pantyhose"
Winter (White coat):
"Irisviel von Einzbern, long hair, pantyhose, thighboots, coat, fur hat"
Dress of Heaven:
"Irisviel von Einzbern, long hair, IrisvielCaster, white dress, navel, bare shoulders, detached sleeves, crown, stomach tattoo"
The Black Grail:
"Irisviel von Einzbern, long hair, IrisvielBlackGrail, black dress, navel, bare shoulders, detached sleeves, crown, stomach tattoo"
Halloween Princess:
"Irisviel von Einzbern, long hair, IrisvielHalloween, thighhighs, cleavage, tail, detached sleeves, wings, horns, demon girl"