Well, about 3TB drives , no need to be greedy but ..
SSD for boot, yes (But no idea which SSD, few of them seems to be having firmware issues, any decent one out yet?)
Regarding warm welcoming, thanks! and about relocation, I agree, sorry for opening the topic at wrong forum category :-/
No backup plans , but is there any possibility that I may need it because of the raid/multiplier setup? (I mean I already have 18TB fulled drives and none of failed or crashed yet)
My old setup: I was connecting my 2TB drives as secondary drive to my PC and download the content , make the disk full then disconnect and connect new 2TB.