You may also want to use a caliper to determine the size of your binding post, then use a good high speed drill to widen the base of the "U" in the spade lug. This will make for a nice tight fit. However, you will need to insure that the "nut" on your binding post is removable so you can slip the spade over the post, then put the nut back on and tighten. Also, if you use this method, take a small round file and de-burr the new opening.
If you are not comfortable using a drill and don't have a way to securely immobilize the spade before drilling, do not attempt this.
Enjoy,
TIC