There is no limit referring to track numbers. You can have as many as you want if the overall size of your music is not larger than the maximum capacity (100 GB) that we offer officially. You can try bigger amount of music, but it is not recommended, because in that case it is simply difficult to search the music, that you want to listen to. On the other hand, the Gateway also needs to index the music content, if you have more files then the indexation process takes longer too. With bigger music database we recommend to use the Gateway Indexer software, which does the index process already on your PC, so after you have used it the Gateway can start the music right away from your USB stick.
There is no exact recommended structure of the music, but you can make it based on Genre(Pop, Techno) or Artist or Album. If you want to find out how to control your music data, please read section Q.