I bought rails for my ssd so that I could then fit it inside my case. After attaching the rails it is still not wide enough for my hard drive bay. Please look at the pics. As you can see it just about isnt wide enough so I cant screw it down.
In my experience those kind of 3.5" hard drive caddies are meant to mount the 3.5" hard drive from the bottom. It looks like your adapter rail has holes on the bottom, at least the one side does. Have you tried to see if you can mount the rail adapter to the disk caddy from the bottom instead of the sides? Are there enough holes and do they line up? If so, you could mount the adapter rails to the caddy from the bottom, then mount the 2.5" SSD to the adapter from the sides like you have it.
I had already tried that, but no luck. I ended up just mounting the ssd to the bottom of my drive. They provide some holes at bottom of the case to do so but was trying to avoid doing so with the wiring getting so awkward. Thanks anyway for your help.