The partitions really do not matter as far as the aspect of data protection go, but it may make it easier to find what you want during recovery.
As far as storing the backups, I would highly recommend storing the backups somewhere other than another partition on the HDD because if the HDD fails it will make it extremely hard to recover anything.
Since you are using Acronis I would recommend doing two backups (assuming you have the space).
First backup just your data. This makes the data portable and accessible from any machine.
Second do a full image copy of the drive in its entirety, and when you do this make any option keeping for the NT signature is selected (Different versions of acronis have this in different places). Imaging a windows 8 system can be hard due to the nature of UEFI and secureboot. If you have a copy of the entire drive with the NT signature intact, then it should image back you your laptop easily. When doing this you can use higher compression to minimize the space that the backup takes.
I cannot stress that without the NT signature intact you will have an extremely hard time recovering the OS. I learned this while designing a network imaging system to deploy Windows 8 to refurbished notebooks.