I just git the ergo performance -also have original that I prefer but too hot. Anyway, I never used the insert with my others but got one to use and it sucks! Am I doinging something wrong? DS is huge-4.52 at birth and over 5.2 kg at 3 weeks, now 3.5w. Would his size be making it so impractical? Trying to fit the inset plus him is not possible. He has great had control already..all my kids did very early..and can roll front to back so very stron. So, given the main reason for insert is hes control, should I not bother? I'll never use it as it is, I'm uncomfortable and he's uncomfortable!