Questions about impedance protection selectors

i am setting up in-ceiling speakers in 4 rooms with their own volume control. if you are using an impedance protecting speaker selector such as niles sp6 or the parasound one, do you need to use impedance matching volume controls? or just standard volume controls?
Someone's gotta know this?????????????????????
I am workin on a similar set up for my parent's new house. The best I have been able to determine from reading product manuals is that you don't want to combine a speaker selector that has impedance matching with a Wall Selector that has it too. This will double up the impedence and severly reduce volume output.

However, by setting the Wall Control's jumpers to 1X or 2X, instead of 4x which is what you would for 4 pairs of speakers, you can utilize the extra amp power when switching off a zone on the speaker selector box. Another alternative is use their passive HUB8 and then set the wall selector jumpers to the correct impedance match. The downside of this is that the amp will always see the full resistance load no matter if you have all the rooms playing music or not.

It seems that Niles is moving toward the impedance matching at the wall vs. at the speaker selector since it offers more flexibility for whole house systems. I can not find a non-impedance volume box that they make anymore. All of the new stuff has it build into the wall selectors.