I don't know much about Vanzurova. Some info?
She was very impressive in her junior year and one of the most talented one in 1990-91. As Matthias said before she is just 183 and it is hard to play on high level as Opp. Also considering Czech has Havlickova as Opp already and big necessity for another OH near to Havelkova, it would be wise to convert her position to OH. But it seems Brambarova and Rosso play as OH (actually they both can play as MB, right?)