As stated, reloading with black powder presents no challenge, keep your payload to 15/16 or one ounce of shot, use the 2 1/2 dram measure or weight equivalent and enough fibre, felt or cork wads to fill the case and allow for the crimp. Roll crimps are best. I don't know of any published data for smokeless loads specifically for 16 gauge Canuck ( or Maxum, Imperial) paper cases but there may be some help on various 16 gauge forums. Play safe, there are no substitutions extrapolation or guessing with shotgun reloading, use only trusted published pressure tested data. I have done extensive reloading with 12 gauge paper Federal, Canuck, Maxum, Winchester, Gamebore and several forgotten Italian brands, the Federal are the best. Look for genuine brass, not yellow coloured steel bases (use a magnet) and avoid any damaged cases. Repeated crimps will deteriorate the case mouths and may only provide 2-3 reloadings and with black powder you will get tiny burn through pinholes just ahead of the metal, the cases should be discarded at that point.