I've tried it on a NAS with a mapped SMB share and also from my computer just to 100% eliminate that it's not a NAS read speed issue (both can serve up 90-100MB/s+. that's megaBYTES, so just under 1Gbit more or less)
Basically, don't bother. It's completely useless because it's so slow. You will have load times approximately 3-4 time using a hard drive. Makes games literally unplayable.
(I'm sure you will ignore this and try it anyway as I ignored the person who advised me to not bother)...
Give it a go, it's satisfying to see it work, but that's it.