Say you have two pieces of furniture, one with Desynth, aura strength 4, another with Lightning, aura strength 6. You would get the Lightning moghancement due to having a higher strength on that piece of furniture.
Each piece of furniture also has an associated element. If you use only one piece of Desynth furniture with strength 7, element lightning, you can fill your house with any furniture that has element lightning if it has a strength 6 or lower, and you will keep the Desynth moghancement. I recommend one Thurible to get a high aura Desynth moghancement, and random lightning element furniture strength 7 or less to get to overwhelming.
Well your getting the desynth moghancement yes, But your also trading mog house space for storage space. so if you work out of your home city anyway this won't be much of an inconvenience.