Geeze....are we now going to get a whole new series of threads arguing whether set screws couple or decouple speakers???
Seriously, IMO you were smart to get the threaded holes if only because they give you options going forward. You should look at the posts here discussing spikes vs. more compliant footers, some of which you can mechanically fasten (i.e., using threaded screws) to your speaker stands and some which you can simply position under the stands. I recently went from using a variety of spikes, to using more compliant, decoupling footers under my speakers. I believe the decoupled (i.e., unspiked) options sound better in my system and I have ended up with damped springs under my main speakers and Herbie’s Giant Fat Gliders under my subs. Herbie’s also makes Giant Threaded Stud Gliders that you could screw into your speaker stands to both level and decouple your speakers. Other considerations you can read about are how your floor construction (i.e., suspended wood or concrete slab) can affect the sound depending on which type of footer you use, and also how raising your speakers (with footers) can affect the sound. Finally, whatever method you choose, there are both expensive and inexpensive options for both spikes and decoupling.