Ankle weights

Hey guys, I am considering buying ankle weights to step up my workouts. I am fit and fairly strong, I lift around 15kg dumbbells during strength training, but I want to increase the challenge of Pilates and any workout that includes leglifting. So my question is how heavy do you all recommend I get? I've seen 0.5kg per leg which seems very light, but I'm thinking it feels heavy when using? Any advice would be welcome 🤗