No, I think I was just being lazy about working my way through what you were describing.
Now that I've taken the time, I believe you are describing the connection of a HV secondary to lugs on a terminal strip, using a section of twisted pair. In which case, you are, in effect, extending the terminals of the transformer to specific new points; so, measuring between the two points on the terminal strip is essentially the same thing as measuring between the two lugs on the transformer.
If my surmise is correct, then you are indeed measuring that secondary winding that terminates on transformer lugs 6 & 7. Inside the transformer, the winding consists of a long length of a specific gauge of wire wound in basically a coil. The winding is likely more complicated than a simple coil, particularly in a transformer with more than one output, but as far as DC resistance is concerned, the main factor is that you are measuring a very long piece of wire from one end to the other. That wire has a certain characteristic DC resistance-per-unit-of-length which is a function of what it is made of, the cross-sectional area or gauge, its temperature, etc. In the specification for the wire, this is usually listed as so many Ohms per thousand feet, or something similar.
The reason I had this note on my copy of the schematic was that I took a DC resistance measurement on the primary coil and the individual secondary coils of the transformer before I hooked anything up to it and made notes about the results on a copy of the schematic. Usually, such knowledge isn't really necessary unless you are designing a power supply from scratch, but I was curious. And, taking such measurements after stuff is hooked up may make for inaccurate measurements, so I took them first.
If all you have hooked up are leads, you can check this for yourself.
You will find, among other things, that the secondary for the low-Voltage supply for the tube heaters has a much lower DC resistance, probably a fraction of an Ohm depending on how accurate your meter is. This secondary terminates, I believe, at transformer terminals 4&5. You will also notice that the leads coming out of the interior of the transformer that attach to these terminals are of a much heavier gauge than the ones at 6&7, due in large part to the fact that this secondary, though much lower in Voltage, provides significantly more current than the HV windings. So, since the wire used in this coil has a larger cross-section and the length is very likely much shorter, the resistance is much lower. Don't worry if your meter has trouble getting an accurate reading on this winding, though; most digital meters don't do all that well on resistances less than an Ohm unless they have a range specifically designed for such work. The other HV winding terminates at transformer terminals 9&10 if memory serves, and that should give you a very similar reading to 6&7.
The primary winding terminates on transformer terminals 1&2 as I recall, and there is no reason not to measure that resistance as well if you are so inclined. Just make sure that you have no power attached if you do so since that is where your AC mains connect.
I believe the main thing Paul Joppa, who designed this transformer, is concerned with is that each lug from the transformer is properly connected to a specific point in the following circuitry. In other words, no swapping 6 for 7, 9 for 10, etc. So, if you take care to follow those instructions carefully and make sure that each transformer terminal connects only to the exact terminal it is supposed to, you should be good to go.
But, by all means come here and ask questions as they come up. I find it's always better to be sure before moving on, rather than having to re-do something later. The only dumb questions are the ones that don't get asked, and the posters on this forum are very, very good at responding helpfully.
