Firstly this is where I got the idea:
1. Go to a new server
2. Create a level 100- Trial character
3. Create a Demon Hunter on that server and level it to 100. This is the time consuming bit but if you are going to long term farm instances you can only do once per day this is how you get your reward - the more effort initially gives you more chances. Those 2 levels don't take long.
4. Queue in LFD with your Demon Hunter on as many characters as you can create.
The Trial Level 100s don't seem able to join the queue but the Demon Hunters can.
Hope this works for someone.