The new listening instructions are pretty clear.
If you want to run 3 subs, you have to run all for the same length.
You could try your Idea, just know, that thats absolutely experimental.
Also not recommended since SC can’t guarantee how they will synergize. You could try, but that would be also absolutely experimental.
If you’d like to try it anyways, runs the subs for a while (2 months min) first so you have a baseline and can determine how the subs feel like.
If things change for the worse after introducing other modalities, you know what is causing the bad results.