Some of my solder joints, while cooling turn that dull silver look. I'm afraid of heating things up to much
A better way to do it is to make a mechanical connection before soldering (half a wrap, then crimp with your needle nose pliers), then use a tiny bit of solder to fill in between the two. (like mortar in a brick and mortar wall) Using less solder requires a lot less heat.
If you just pass leads through the terminal holes, then expect to use a lot of solder to hold it there, you'll end up with an unreliable build that also won't quite sound as good.
-PB