I keep the bra in my pump and put it on over my nursing bra JUST when I'm pumping. I learnt that it's easier to put the horns on your breasts first and then just poke the back of them through, then attach them to the rest of the pump. If I could do it over though, what I would do is take an old bra and put it on, then with a marker, mark when the centre of your nipple is - then just cut a hole with about 2cm diameter or so. I'm sure it would work just as well. I'm part of an exclusive pumpers group on Yahoo and a lot of people there have done this kind of thing and swear by it. Some even use SHIRTS but I imagine a shirt would have to be on the tight side in order for it to work.
I never used breastpads this time around as I didn't really leak hardly at all. But if you did, I would just attach them to your regular bra and use the Simple Wishes over the top when pumping.
Yes, the Simple Wishes just has two sizes, but it has a LONG velcro section so it is VERY adjustable. They have two sizes for the front - depending on how close together your "twins" are.
I'm quite busy next week but if you want, maybe one day the week after I can meet you to show you? If you're in Chai Wan, I could meet at Cityplaza or something? If you're interested, PM me.