Morgan's carry cot part was a bit smaller than the average ones, as it was made to be taken out & moved around easily. Max may last in his a bit longer although no way 6months!
Max went in the seat part of his travel system last week at 10weeks. I just kept him either flat or slightly tilted. No more than they are in a bouncer. Morgan was in the seat part from 12weeks because he outgrew the carry cot on his!
My friend never used a baby seat or pram with her twins she only ever used a pushchair. They were fine. My little one is nosey and wants to look around haha xx