Sorting audiobook mp3s

'Just to summarize - it seems that the player does not support naming convention for track tag like “/” and additionally it has an issue sorting files having numbers with more that 2 digits. "

i have not had any problems with the player sorting 3 digit track numbers. Having the numbers with leading zeros is what is needed, ie 001, 002,… , 099, etc. I do find it easier though to start numbering at 101 when using 3 digit track numbers.