Help! with Surround 5.1 reverb set up for Orchestration please

Can anyone help me understand how to set up an East West Opus template which uses a pair of East West Opus reverbs for front and rear?
Let’s imagine there is only one instrument. A Piccolo. This sends to the" Woodwind Group" that then sends to the 2 FX channels which (I think?) use the front speakers and the rears to create the false “Surround” reverb. The reverb I am using is East West Spaces 2. I want to leave the sub and middle channel clear.

I have been trying, but the advice is conflicting, sometimes using child busses and sometimes using fx channels only. I am finding this a real challenge If I can get one channel right, then I shall be OK.

Thank you all

Z