[Raynor]

He successfully (and repeatedly) instigated mass invasions against his enemies from Angmar

Maybe; but Angmar fell nonetheless.

in 1851 with the Wainriders

Defeated eventually

and in 2000 the Nazgul seized Minas Ithil

In 2002 actually.

Sauron would have done everything he could to force such a man-to-man confrontation because the odds would have been impossibly stacked in his favor.

I am not sure what you have in mind; if you are reffering to a man-to-man confrontation with the ringlord, I think we both ruled that out from discussion; if you are referring to confronting individual soldiers, I don't think he would actually avoid, not force such combats - perhaps you could explain.

Mainly because I didn’t see your point or how it related to what we were talking about

My point is that a ringlord's chances to defeat Sauron would increase the sooner he got the ring and started building his empire; there is either a barrier of communication, or we are starting to argue in circles. I am fairly convinced that there was a time during the third age when Sauron could have been defeated even by a non-ringlord; a ringlord would have achieved that victory even quicker. On the other extreme, there is the year 3018, when Sauron is almost ready to strike successfuly the ringlord-less west. Perhaps you are right that the west had at best months to prepare against Sauron; or perhaps a ringlord could extend that period sufficiently enough; we don't know that. Galadriel seems to credit Frodo with the ability to wield the one ring in order to submit other wills, perhaps a more powerful wielder could do that on a far larger scale. Seeing that whoever wields the one ring knows all the thoughts of those who possess the other rings, perhaps even the nazgul are vulnerable to, at least, information leaking. Given time, even Frodo apparently could have mastered the nazgul:he "needed time, much time, before he could control the Ring or (which in such a case is the same) before it could control him; before his will and arrogance could grow to a stature in which he could dominate other major hostile wills [of the nazgul]". My ideas are not ill-founded, as Tolkien too considered that, if an elven ringlord would/could emerge, he/she would build armies, etc:

Originally Posted by Letter #246

In the 'Mirror of Galadriel', 1381, it appears that Galadriel conceived of herself as capable of wielding the Ring and supplanting the Dark Lord. If so, so also were the other guardians of the Three, especially Elrond. But this is another matter. It was part of the essential deceit of the Ring to fill minds with imaginations of supreme power. But this the Great had well considered and had rejected, as is seen in Elrond's words at the Council***. Galadriel's rejection of the temptation was founded upon previous thought and resolve. In any case Elrond or Galadriel would have proceeded in the policy now adopted by Sauron: they would have built up an empire with great and absolutely subservient generals and armies and engines of war, until they could challenge Sauron and destroy him by force.

***Concerning the mastery of the ring, Elrond stated: "Its strength, Boromir, is too great for anyone to wield at will, save only those who have already a great power of their own."

Between the coming of Sauron to Dol Gudur in 1100 and some years before Pelennor Fields there is just speculation, and perhaps it is just better to agree to disagree since we all put our arguments forth and I kinda dislike the tone of the discussion.