Running Final Cut Pro X Projects Externally From Macbook Pro Laptop Using Thunderbolt

Hello.
I have a MacBook Pro (Retina, Mid 2012) with 8GB of RAM and a 2.6GHz Intel Core i7 Processor, currently running OS X Yosemite Version 10.10.1.
I have an internal SSD with 500GB of storage and a 2TB 4th Generation Time Capsule that backs up my computer daily.
I've been editing video with Apple's Final Cut Pro X for quite some time now. I usually have imported footage in an MP4 format in various events in Final Cut Pro X.
I am running Final Cut Pro X on version 10.1.4.

I've now come across a problem where I am out of space on my internal SSD in my laptop due to all of the Final Cut Pro X projects.
Even after archiving older projects to my Time Capsule I am still out of space on my SSD.

I want to run all of the projects in Final Cut Pro X that I am currently working with on an external SSD that is run through my thunderbolt port for the fastest transfer speed (in real time as I edit my videos) rather than through my USB 3.0 port. I want to utilize my thunderbolt port while still being able to use my laptop for portability, in order to do this I want to use the smaller SSDs (2.5").

My Questions Are:
1. I was thinking about getting the
Seagate Backup Plus Portable Thunderbolt Adapterhttp://www.amazon.ca/Seagate-Backup-Portable-Thunderbolt-Adapter/dp/B009HQCARY/ref=sr_1_1?ie=UTF8&qid=1422471747&sr=8-1&keywords=seagate+thunderbolt+adapter

but it is very expensive for an adapter ($224.50 Canadian Via Amazon.ca), so my questions are:
Is there any alternatives that I could use that are still a thunderbolt adapter that are compatible with 2.5" SSDs?
And would this be the right thing to get in my situation, would it match my needs?
Lastly, what kind of speed should a 2.5" SSD have if I want it to run my Final Cut Pro X Projects while I am working on them?
Thank you.

Editing off your system drive is always a bad idea. Get a good sized external USB3 or T'bolt "media" drive to put all Libraries and media on.

Drives, even SSD, have bandwidth limits that video will eventually max out.

1- Verify all connected drives, especially your system drive has 10-15% of its total capacity reserved as free space.
2- Move all Libraries and media to a dedicated media/editing drive.

Hi Solid,
Always a good idea to move all media to a different drive than the boot (OS) drive.
Start with what are your actual needs concerning throughput needs and match your system to that.
Throughput speeds are system dependent and limited by the slowest part within that system.
For a single external drive spinning hdd or ssd, there is no speed difference between USB3 with USAP and Thunderbolt 1or2. You need around 3/4 ssds or 9/10hdds in RAID 0 to saturate USB3 that has UASP (USB Attached SCSI Protocol) enabled, therefore the drive(s) itself is the limiting factor, not the I/O port. Be aware not all external USB3 devices support UASP, but all Macs with USB3 do.
See this article by Larry Jordan on throughput speeds… www.larryjordan.biz/app_bin/wordpress/archives/2559

As far as the Seagate adapter(s) they do work for any 2.5 inch drives that can be powered by USB. You could get either the TB or the USB3 versions, but it is a bare adapter not an enclosure. You could also check out the Inatek 2.5 external enclosures and get the USB3 with UASP for less money. Not a bad IMHO. There are now a few versions.

Hope this helps, Greg