I found the best way to increase population size was to use a food processor to cut up all the food really small. The worms eat it so fast and multiply like crazy.
Then, when the bin was established nicely, I just chucked the stuff in as it was and let it do its thing.
I don't think it really matters what way its done - at the end of the day, as long as there is enough food in the bin, the worms will eat it and multiply eventually.
My worm bin is a 200L food grade barrel that used to store commercial olives. It stays outside (we have a climate similar to Arizona / Cali), so keeping the temp and moisture in the bin is the hardest thing initially, but in all honesty keeping worms must be one of the easiest things associated with gardening IMO.