Speakerbox volume?

Hello all,
I have the speakers Klipsch Pro 180 RPC and Klipsch Pro 180 RPC LCR.
For this I would like to build speaker boxes.

What volume do the speakers need and should the boxes be stuffed with absorbent cotton or not?

Unfortunately, the support does not answer, so I try it via the forum.

Thanks for the help
greetings
Patrick