I use 4" standard zip ties to hold down Fastrack and Menards 3 rail on my year-round Christmas layout. The mounting holes in both the Lionel and the Menards are the perfect size for the zip ties, no drilling needed.
I drill an 1/8" hole with a 6" long bit through the track hole, 2" foam board and the 1/2" plywood. Insert a zip tie then another zip underneath to secure it all.
This is my first layout so I can't compare the sound but it's a lot quieter than loose Fastrack on a hardwood floor!
I too like the 1/2" binder clip method for the Fastrack, I'll try that next.
Thanks all - Jimmy