Hey,
what you need is an second Account/Friend which is connected with your main account with the new RAF system.
Step 1. Take Your Twink To a WSG BattleMaster and Que.
Step 2. Now, your friend must level your alt with the RAF bonus levels
Step 3. You should still stay in the que and can confirm the battelground.
Step 4. Have Fun in the Level 19 Battleground with your Level 60 Char
Sorry for my bad english but i hope you all understand what i want to say.