If it helps none of mine can stretch out on the platforms, We have got the Polecat as one of our ones and they do stretch out on the top platform, they just have their back half and head and front legs hanging off the ends
(Mine are tall enough to be able to stand up and put their paws on the worktop)
Is Kylie a very long cat or just 'well covered'? Does she always sleep stretched out or does she usually curl up?