I used to prepare quite a lot of presettings -in round, not square
bezels- and since time was a concern, I would ask the custmer to
provide me with tubing of the diameter needed -around 3,5 mm-, I
would then saw that tube into 15 to 20 cm long pieces -long enough to
hold them comfortably with your hand- and I would start setting the
stones at both extremes of each piece. Once a batch of stones are set
(if I had cut five or six tube pieces, that would be 10-12 stones), I
saw the extremes to the needed length off the tubes -with the stones
set- and I end up with 10-12 nice small bezels. And then the process
begins all over again. At the begining you can perfectly hold the
tubes with your hand -this makes the process really quick. But as the
tubes become shorter and shorter they are more difficult to hold (I
used to use a glove in my left hand), to the point that you have to
start using a wood clamp or somenting to hold them properly if you
want to make the most of the tubes.
I hope this can be helpful.