Thanks to everyone for their knowledge sharing in this thread:
Thought I'd share specs for future readers, particularly Canadian shoppers
* Model: Mid-2014 13" Macbook Pro Retina - 256GB (Running Mojave 10.14.4)
* Adapter:
"Rivo" on amazon.ca - might be an OK alternative for Canadians. Shipping is a pain from Sintech/ebay, this seems to be the cheapet option with Prime shipping for us for now. It looks quite similar to one of the X'ed out models on the first post...but we'll see. I will update if this fails at a later time but another poster had success with this seller.
* SSD: 1TB HP SSD EX950 M.2 (on sale on newegg for about $220 CAD, ~$160USD)
Steps:
* Back up TimeMachine...Don't forget to include your Applications in your TimeMachine back up (I had forgotten that was in my exclusion list..wasted a couple hours)
* Set up a USB Mojave installer
* Swap out the SSD with new SSD + adapter
* Erase/format new SSD using USB installer (Option on reboot) and install OS X onto the newly installed SSD
* Restore from TimeMachine
* Side note: Got kernel panic errors when I tried to restore from TimeMachine back up, but USB installer worked fine
* Encouraging read/write speed upgrade
* Fans went crazy initially before calming down - monitoring temps with istat
* Ran terminal to set up hibernatemode 25 "sudo pmset -a standby 0 hibernate mode 25" (not sure if anything else needs to change?)
* Boot ROM is 151 - unchanged with update today to 10.14.5.
Disk Speed Test (Blackmagic)
Write - OEM 256GB: ~350MB/s ---> HP EX950 1TB: 1302MB/s
Read - OEM 256GB: ~657MB/s ---> HP EX950 1TB: 1461MB/s