A little project I've been messing with the past few weeks (consequently the one I cut myself on)...a two 2.5" hot swap bay that will take the regular Dell caddies. 

I kept everything as simple and serviceable as possible. I'm just using some pass through SATA connectors which can be replaced if broken or damaged

(https://www.amazon.com/gp/product/B07CKXFKM5/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1)

Then I made a custom power cable using some cable creation SATA power connectors and a micro Mate-N-Lock connector. The wire is some Turnigy silicone wire I had left over from building a multi-rotor which should be way overkill for the task...2 SSDs shouldn't pull more than about 13 watts at any one time. Now my other concern was if the motherboard would be okay supplying that. The drives do work but I'll have to do some more testing to be sure.

I have a couple older drives I can sacrifice to stress testing. I figure if I burn up a Gen I motherboard and a couple very old laptop drives during a stress test then oh well.

If you're wanting to make your own power cable for the DVD/TBU_PWR port the connector on an R710 motherboard, you'll need a 3mm micro Mate-N-Lock 4POL female connector (Part #794617-4) and the micro Mate-N-Lock socket connectors for each wire (Part #794606-1). Looking at the GP700 cable offered from Dell you'll be able to figure out where to place the red 5V wire, yellow 12V wire, and your black ground wires.