I have so far used 3 external hds on my nexus 10
1- samsung 1tb 2.5" without external power
2- lacie external 3.5"
3-one of those caddy things where you just pop a sata drive in (vertically). This is not an enclosure as such. All 3 work. the drives in 1 and 2 are as purchased. with 3 i just use any old sata drive.
and from what you say can you browse your HD from the tablet like using the computer if you have the Y cable to provide power for the HD and will this method work for the Note 10.1 or only works with Nexus