some great tips already, here's what i done:
once the male plant is isolated from the rest of the females, get a bamboo cane + string,
bend the main cola of the male over just past 90 degrees and tie it in place,
then i used a few empty photo frames - take the glass sheet out, then placed each sheet of glass under + as close to the flowers as possible (i used whatever i could to get them to the required height - books, boxes, anything to get the glass perfectly under the male flowers),
then it's just a case of waiting until the first flowers show signs of opening,
i use the tweezers as well to 1st tap the opened flower to collect remaining pollen, then finally pluck the used flower off, and with the tweezers give it slight taps on the glass as their will still be pollen in there,
get rid of the used flower (don't want the moisture in there killing the pollen),
to harvest in stages and collect the pollen to use for eg. in a few days, i'd put it all in a clean shot glass in stages as the pollen falls, keep the shot glass in a cool, dark area of the house until ready to use, i only kept it there for 2-3 days at most so i'm not sure how long it'll stay viable like this
peace
Herb