Should carseat be upright as possible?

[CastleTower]

Haven't been able to find the answer to this by googling or in the manufacturer instructions.

Basically, my 9 month old has outgrown his infant car seat. He's not at the maximum height/weight yet, but he has a very long body and shorter legs, and it's clear his body is too long for it. (His head is 2cm over the top of the head rest.)

So, he's going into the Britax Dualfix we already have, obviously rear facing. This seat has 5 or 6 recline positions, but doesn't say what is best practice. Do we put his as upright as possible? Or is a bit reclined safer? Does it matter as long as he seems comfortable?

He very very rarely falls asleep in the car, so I'm not worried about his head lolling forward or anything.

Thanks.

It doesn't matter :)

In theory more upright is safer, but there is only about 10 degrees difference between the most reclined and most upright position, it's been tested in all the positions, they are all safe.

They give you different recline positions because the angle of the seat will differ slightly in different cars, and also so you can find what's most comfortable.

Thanks, Bertie, that's a big help. I will stop overthinking it then!