My newborns have always gone behind the passenger seat. It makes it easier to get them in and out of the car and they are curbside.
As i had more kids and they got older, the youngest is behind the passenger, my 5yo is in the middle (he can just climb over to the front and get out the passenger side) and my 9 yo sits behind the driver.
I had VB but i still suffered a very sore back for months afterwards, i wouldnt have coped very well getting a capsule in and out of the middle seat.