Now, as the moderator as am I on NTSC Records, I made a list of the good characters for tracks on NTSC version, to help other people who don't play on PAL.
Crash Cove, Roo's Tubes, Tiger Temple, Coco Park, Mystery Caves and Dingo Canyon: Obviusly Dingo or Tropy, but sometimes Papu it's good for Mystery Caves.
Blizzard Bluff and Sewer Speedway: Papu, Dingo, Tiny or Tropy.
Papu's Pyramid: Penta Penguin it's always better, the best times you can reach (for me) are 1'17''XX and 24''XX.
Dragon Mines: Ripper Roo it's good (for lap times), but you can use Crash or Cortex on course times.
Polar Pass: I use Crash (for a better turnin') but sometimes it's better Coco or N. Gin. I wanna add that Pura it's good for lap times
('coz I did 42''86 lap in video with Pura)
Cortex Castle: Believe me, Crash is better for course times, but (obviusly) Polar or Pura are better for lap times.
Tiny Arena: (same as in Cortex Castle)
HAS: Penta all the time!
N. Gin Labs: If you want a better turnin', Crash or Cortex, but better Coco or N. Gin.
Oxide Station: Crash or Coco.
Slide Coliseum: Just impossible take the Shortcut with every character which isn't Dingo.
Turbo Track: Roo, Pura or Polar (but Penta it's bad)
IF I need to change something, or If you think some of this isn't right, tell me (or edit it).
Hope this options are helpful for you^^