Data Volume lost after disk replacement on Readynas Pro 6

I have decided to give it go myself.

Read a lot, found that raid/parity setups are not really good solutions anymore in these days where disks are so much larger and so different from those when these systems were created (1995-ish?). Raid 10 seems to be the current preferred setup by professionals. (no complicated expensive parity calculation, disk space is "cheap"). I further found some real good insight on recovery chances: according to one: in 85% of cases it can be solved with software, in 10% it is the circuit board, which you can even hotswap and I have 5 spare.., in 4% it is the heads or the platters, and in 1% it is the motor.

So  I reckon I have a larger than 95% chance to recover my data. Worth a try.

First port of call is to make bit by bit images of the drives so that I don't have to use them for the actualy inspection and recovery of the data. I use the free linux version of r-data to make them, so that I have some idea of the chances for succes before I buy the software. I could also have used ddrescue, both these tools  read the disk sequentially (as an old fashioned record) which is the least demanding for the (now fragile) HDDs.

Bought a esata hot swap cradle, filled the nas pro with 6 new disks (JBOD) and started with r-data to make images. The original disk2 (which triggered the problem) can't be read. That is a candiate for another PCB, and I could eventually replace the heads if necessary.  I am currently imaging nr5, the second one that give up. Apart from a few strange noises in the early stage, the imaging process is proceeding without errors. I think that if this one works and the sixth images fine I should be able to restor the array.

I am not a pro as I stated above, any advice is welcome, to be continued.