I guess the music really depends on what was danced. A.I. Barkovetz's webpage on 'The history of Russian Court etiquette' gives some information on the type of dances of Russian court balls (
http://www.rosizo.ru/eng/japan/etiket.html). " The orchestra started playing [a] polonaise. The Emperor led the first pair, usually with the wife of the Dean of the diplomatic corps. The Arch-Marshal surrounded by the masters of ceremonies walked in front of the Emperor, as if laying the way for him. «The Court Polonaise was truly a [hierachy]», — remembered the Head of the Registry of the Ministry of the Imperial Court A. A. Mosolov. (Mosolov А. А. At the Court of the Last Emperor. M. 1993. P.141). Then was the waltz's turn, then came mazurka, and then the guests were led into the room where dinner had been served. Cotillion was to finish the festival." Strauss of course performed for the Russian court but a feature of court balls in the later 19th century was the playing of mainly Russian music, in line with developing nationalism, and there were numerous composers who wrote for the court. Polonaises by Oginski and Chopin were popular but the polonaise from Glinka's opera 'A life for the Tsar' was especially popular for court balls, according to the catalogue of the first Amsterdam Hermitage exhibition 'At the Russian court', which has an extensive section on Russian court balls which is very interesting.
The Wikipedia entry on Osip Kozlovsky (
http://en.wikipedia.org/wiki/Osip_Kozlovsky) has an interesting reference at the end to recordings including his music and that of contemporaries in 'Music at the court of St Petersburg 2' which seems to be reasonably easily available, and although this is a bit early for your period there are other useful recordings such as 'Dance Music From Russia: Waltzes & Polonaises CD' (
http://www.cduniverse.com/search/xx/music/pid/6974105/a/Dance+Music+From+Russia%3A+Waltzes+%26+Polonaises.htm) which is perhaps a little more in the right area. However, the opening polonaise of an imperial ball was a stately dance, in which the most senior performers took part (who would not necessarily have been that young) so the music may not have been especially up to date.
