I have a pair of RSV-L4411's, and I assume that not much has changed. After inserting any given drive, give it an extra very snug push. On a rare occasion, I also find that one particular drive just seems to hate being in one particular slot and gives CRC errors. Relocate. Actual drive failures are rare. A lot of time its related to CRC errors and crappy cables / them not being seated 100% correctly.
That and and in cases like this with tons of cabling, the urge is to tie up wires. Never do it. Let them sit randomly. Removes any chance of cross talk. You can tie up the power cabling to the bays, but in this case, make sure that they only cross the sata cables at 90 degress