Pervasive 8.6 (version 8) has a file size limit of 16GB, The amount of opportunites you can add will depend on this number as well as the hardware you are using for your server. Although the DB can handle up to 16GB of data pulling that data off a P3 800Mhz with 256 mb or memory will not be fun. If you are concerned that you will breach this 16GB mark in a year or two consider moving to SQL and whenever you need more juice you can just add hardware.
Voted most likely to be a Hill Billy, Mental Patient or Chimpanzee.