Aubergenie - we have it fitted as far back as it will go, it is fitted as per the safety instructions and by a someone trained, not us.
The way we have it is shown on page 4 of the instruction manual here:
www.securatot.co.uk/images/manuals/Securatot_Brio_Zento_GB.pdf
(thats page 4 of the manual, not the pdf page 4 IYSWIM) and look at the central picture, in the instructions its described as:
For a more reclined installation for a young child, or if there is limited
space in the back seat, fold the front foot underneath the BRIO Zento and place the heel on the vehicle
seat, and ensure the back of the BRIO Zento rests against the back of the front seat.
This has given us a nice recline, without taking up any extra space. DD can sleep in it fine, no head lolling and no bruising !!
I really can't see how DD will be bruised by this chair, it seems as well padded as any other seat, unless Adventuredad means she'd be bruised in an accident - tbh as long as the seat performs in an accident and keeps her neck and spine in one piece I can cope with some bruising.
Adventuredad - I'm sure there are better seats but unfortunately RF seats are hard to find and its better to have a seat fitted by a trained car seat fitter than another one which although comes recommended you can only buy online, therefore having to fit it without any professional guidance.