I came back to this zRam/zSwap idea and decided to give it a longer test run on my low traffic site hosted on a 1GB Digital Ocean slice. Actually the idea came back and Microsoft just enabled RAM compression for all users on Windows 10 and it seems to be doing its job on my cheap Baytrail tablet.
Anyway, been running for 24 hours now and so far the system has not yet touched the physical swap at all. I also radjusted the Swappiness back to default value 60, rather than 10.
FatMoomin:~# cat /proc/swaps
Filename Type Size Used Priority
/swapfile file 2097148 0 -1
/dev/zram0 partition 508936 208060 5
So far nothing unusual in the CPU loads either, but again this is a low traffic site. Few hundred views per day and most are passive readers.