Here is exactly what you need. I have three of this exact setup for my GSDs.
I rotate between 5 sets of Mini Educators. Have had all 5 for years, and they're still performing flawlessly. Can't recommend them enough. Buy the good stuff once, and be done with it IMO.
Another thing worth noting is the contact prongs are really important for proper effectiveness.
I highly recommend this particular contact setup for a long thick haired breed like yours.
With the stock prongs, you will have poor contact, and thus have to raise the stim level to get it to actually reach the dog, but if contact points manage to actually make proper contact under the hair and you stim them at that level, you will inflict some serious pain.
With the winged contact points, or the extended reach contact points (not as effective on my Aussie, I've tried them), you can set a consistent stim level and it will provide that stim level despite the thick hair. My dogs with long hair also seem to find the winged versions a lot more comfortable than the extended prong style contact points meant for long haired dogs, as you don't need nearly as much pressure on the contact points (tightness on the collar itself to press them into the hair/past the hair) in order to get proper contact.