From personal experience the best milk flavor comes from.Rikken and Hasegawa flavors of Japan.They also have an excellent vanilla flavor.You just have to specify the specific profile as there are hundreds if not thousands of variation of both milk and vanilla flavors from flavor houses. .Givaudan ,symrise , IFF had their own.good versions ,These later companies had good dry flavors as well Find their representatives in your own country so they can give you samples…
The selection of flavors starts by asking a specific flavor profile .: For milk, it can be fresh milk, creamy ,condensed milk, etc with specific notes descriptors like lactones,etc.
Vanilla can be bourbon, Madagascar, Tahiti creamy, caramelic notes, etc…