Hi Chaz (^_^)
I've never done before but...
I read in a great Sans. book, B. Juan Chahinian's "The Splendid Sansevieria",
he recommend a pollen storage technique that is to pick up pollen with Q-tip,
then cut the Q-tip stick (with pollen grains sticked on) and store it, head up
in a little container, an empty roll photographic film container, with fill salt,
1/4 of the height of the container - salt keep the pollen dry but not too dry as silica-gel.
Keep the container in refrigerator. He said he successfully keep the pollen 10 days.

He said he touch the stigma of each flower with the pollen laden tip, several times.
yes, this has to do it at night when the flowers open.

Stephania,
Thank you so much for your reply. I am expecting the flowers of the trifasciata to open any night now and don't want to lose the pollen as the cylindrica will be a couple of days to a week later at least.
Regards, and thanks again. I'll post as I progress, hopefully with photos.
Chaz