At one time I had all eight Tüür symphonies. Sadly, I lost some in a hard disk crash, not having burned them the CD in time. I'll do some digging in my various external hard drives and see what I might still have.
If you do locate a copy, Latvian, that would be great. At the same time I am following up on some (very, very tenuous) leads in Estonia. I'm not especially hopeful but who knows? I'll let you know if anything comes of it.
Brian
http://www.emic.ee Contact the EMIC and see if they will burn you a copy. They are usually very helpful.