Perming Afro Caribbean hair?

Hi all , I have been hairdressing for many years and had lots of experience with perming. I have been asked by a friend (who has Black Afro hair) if instead of her having a relaxer on her hair if I can use our more gentle perm solution to perm a softer curl into her hair... I know structure wise the hair reacts very differently but I just needed any advice anyone can offer before we try it ? ( i will probably do a test peice first ) tia for any help :)