The MIT picking document seems to go along with the pins on the bottom idea:
The nice feature of a lock with the springs at the bottom is that gravity holds the key pins down once they set. With the set pins out of the way, it is easy to find and manipulate the remaining unset pins.
Although I think they are talking about locks that are on doors and not hand held.
Just wondering if anyone else holds the lock this way or if I should change my technique to the more popular one.