Just a small remark Paul: The following statement,
"(to achieve 1:1 it needs a 5T/6T filter - unless you have a D2x) " is incorrect. I take it you mean going to HSC mode with the D2X wll give "more" magnification, but of course that is not true. You get a tighter cropped area but details are rendered identical in size. Magnification is a scale, not an absolute quantity and is independent of the imaged format.
I share your enthusiasm for the 70-180, a shame Nikon has discontinued it.