I can tell you how I manage backups. To start with, there are two types of problems I try to prevent. One is a hardware failure and the other a software failure. Software problems are from my experience the hardest to deal with and occur the most often. Let's say for some reason you lost a file or a file is corrupt or a program or you installed something that messed with other things....
Raid helps with hardware issues but does nothing for software issues so I don't use it (unless Raid 0 for speed). What I do is run Time machine on one drive, have two external clones ping-ponging 2x per week. Have two external clones ping-ponging 2x per month that get stored remotely. I use CCC (great program) for the clones.
My strategy works pretty well and only once did I need to recover something from the remote clones. You'd think that would never happen but Time machine became corrupt and a missing folder had already migrated to the on-site clones. Only my remote clones had a copy and then only 1 of the 2.
My system is not perfect but it is redundant. With TM I can go back and look for old files and with my clones I can go back 30 days in case of emergency. Hardware loss is very very easy to deal with. The downside of my strategy is the 30 day limit on disasters and the fact that I must bring home a remote drive every 2 weeks and then take it back to my office.
Dual TM drives would make my system better but I can live with the 30 day disaster limit.
...disclaimer...I created a media server via apple TV(s) for my family. It took so much time to create (months) that I decided to take backup very seriously.