This doesn't answer your question regarding Tri-X, but might I suggest you try Ilford Delta 3200 developed in Ilford DDX? It is very fine grained at 1600 and 3200, and has a long tonal scale. It comes in both 35 and 120...you can easily go to 6400 and above with an expected increase in grain and loss of tonality, but far, far less than Tri-X. This is also far superior to Kodak TMax 3200 and comes in 120 as well.(posted 8850 days ago)Ilford's web site has a fine printable data sheet on it and an excellent review by Francis Schultz.
http://www.ilford.com/html/us_english/homeng.html