The two latest posts on the Tyndale New Testament blog contain some interesting further comments about the edition and its preparation.
The edition was based on Tregelles’s text because
by starting from Tregelles we go back beyond Westcott-Hort and their influential and lucid textual theories, but not as far back as the Textus Receptus. We could have opted for the text of Lachmann too, but I think that Tregelles is more explicit, and certainly more accessible, in justifying his methodology and theoretical approach. Another reason is that Tregelles is the most recent critical text that was not included in the triad of texts used to create Nestle’s first edition (Westcott-Hort; Tischendorf 8th; Weymouth [in itself the result of a comparison of editions]) or fourth (Weymouth replaced with Weiss).
Most people who think for a moment about the text and the various forms in which it appears, solve the question the same way as Plato did. Different manuscripts with their slightly different wording, and even different translations of the text in a wild variety of languages, all constitute different instances of the same text.
This same dynamic often functions unconsciously too when congregants in a church setting might “open their Bibles,” agree that they are all looking at “the Bible,” and yet have different versions like the ESV, NIV, or NRSV of the “same text” among them.
For these posts’ full comments, see The First Step: Digitising Tregelles and The Text of the New Testament, of an Edition, and of a Manuscript on the TNT blog.