Which RAID configuration and how does back up files work on Windows 10?

MAIN PROBLEM:

What is the best way to setup server's memory, RAID and Backup wise?

Currently I have a PowerEdge R730 server and a MD1400 (just a bunch of disks). Our OS is basic Windows 10.

The PowerEdge R730 has 6 drives each 6TB, which is 36 TB.

The MD1400 has 12 drives each 4TB, which is 48 TB.

Total 84 TB.

I am unsure what is the best practice in 

1) Choosing what RAID system to use

2) How many virtual drives to create, (related to which RAID system chosen)

3) And by extension how to set up Windows Backup

My current idea is to:

1) Create a virtual disk for Windows Backup on MD1400 that is 44 TB (11 physical disks)

2) configure it to RAID 5, so usable memory is (40 TB)

3) The other memory available (40 TB), will be configured to multiple smaller virtual drives, and each configured to RAID 0

4) Finally, through Windows, I select (11 physical disks) virtual disk Backup for window back up

OTHER CONCERN

We have already downloaded a bunch of software on the OS, which we would like to keep and not have to re-download again. Is there a way to create a back up to boot from? What would be your recommendation? 

Please reach out to me for any specifications you may need.

Thank you so much.