Modification of speaker cables

You could see if you can get them re-terminated. The cost should not be too much. Are these gold spades I assume? I had this problem once with other brand and was able to carefully spread out (bend) the spade forks enough to fit around the wider binding post. Bare wires are hard to tell. It should work, but it probably increased the corrosion possibility of the copper ends. I am sure someone has tied this and hopefully will post. There was a post recently of someone who took apart the terminator boxes.

I agree, reterminate. But how much bigger? Is it Dremel can't fix bigger?

Bare wire is better. The transition from one material to another is always a problem because the music signal can become degraded. Spade and banana plugs are convenience items.