Hi Twiglett, I'm afraid I've only used a mechanical pump which you could adjust all these settings! I think I preferred something in between the long and the short, and rhythmical - sorry not much help! I guess you're supposed to try and simulate the baby's sucking action so maybe think about how your little one is and find that rhythm.
As for your boobs, I think they're smart enough to let-down more as soon as you go back to them, ie. if you decided to express every couple of hours after a day or so your body would adjust to this demand and produce a healthy quantity to that timescale. If you up'd this to every 30mins it would probably do the same (but you'd end up with constantly full canonballs!). I would express either first thing in the morning (after the first big feed of the day, eg. 7am, you always seem to have more milk in the morning and it catches up in time for the 10am feed) and definitely at any time a bottle was given rather than a boob. HTH
You need motherinferior - she's the queen of expressing