Cabling Question -Only One Prong of Spade is Contacting Terminal.

go bare wire

It is recommended that you go back in and check the tension a few times, check the tightness.

as this arrangement can loosen more easily than a best fit spade arrangement.

the vibrations and subtle motions can make it so, and will.

So check those connections again, and then do it again about a week later. Just to be sure.

Just..check the security and quality of the connectivity every now and then -- is the byword on this particular methodology of spade application.. 

Essentially, there is enough connectivity for a excellent electrical contact quality..but..not enough friction or frictive area in contact, to ensure a stable connection in the physical realm, in comparison to a properly fit spade.

I have used that method previously, and whatever degradation in sound, it was so slight as to be negligible, if audible. 

Watch out how vigorously you cinch down on the spade, because you could bend/compromise it. 

Actually I ran my Magnepan speakers just like that for years....
Dont worry, just enjoy the music!