That's good to hear. Glad that it worked.
You read that some like to decouple the speakers from the floor. Others believe that you have to couple the speakers to the room, for best performance. Me, what ever works, is fine! Maybe even try both. Put the speakers on a concrete paving stone, then isolation blocks under the slab. It might further improve performance?
When I worked at a CD/DVD replication plant, our Mastering Cutting Lathes rested on a huge granite slab. It looked like an 8' long tombstone! But, under each corner of the slab, there was an air bladder, that floated the slab from the floor; cancelling all external vibrations. It worked really well to isolate the Lathes. That's why I wondered how it'd work under your speakers?
As to Pierre Sprey of Mapleshade, he's an eclectic man. A bit of an eccentric, but he has excellent ears. And while some of his products seem unorthodox, I'd trust them. Glad that you found a cheaper variation that worked too.