dragging off image 1 and progressively enlarging it to compare it alongside 2-4, it looks as if you are better off doing a more severe crop from just the basic lens. The converters appear to introduce chromatic abberation without any more detail.

Or isn't that what I am supposed to say/find?

If it is you have saved me another £140-180 (temptation, no money anyway) getting TCs for my Sigma 50-150