I know what you mean about ‘hard and wrinkly' !
I have used several patches and have found Estradot to be the best at staying stuck
I bath everyday, sometimes twice and the patch doesn't budge.
Not only is it the smallest patch I've used but the best material - soft and flexible, even after getting wet.
I put the patch on the top of my bottom, alternating sides, so bikini bottoms keep it covered.
I do take spare patches just incase