Drum stock settling time...
Drum stock settling time was (still is?): AVGAS 1 hr per foot; AVTUR 3 hrs per foot. 205 litre drum is about 3 ft tall, so 3 hours for AVGAS and 9 hrs for AVTUR. Caribou SOP/SI had a clause which read something like '...unless urgent operational circumstances prevail' but you had to have a very good reason.