I don't disagree with you Marches - it all depends on what your land will hold. On reasonable land I would say that the ideal scenario is to have every ewe rearing twins, but if your ground is harder then that could be too many sets of twins. This year our ewes scanned at nearly 170% - very high for welsh mountains, and rather more than I would like.
Sally re not flushing - I know where you are coming from and in some ways to not actively flush would reduce our twin numbers, but on the other hand, havin a very tight compact lambing period is very important to us, especially as we have to have ewes lambing during the set period of our lambing course. We just wouldn't get the same tight lambing of we didn't flush, so I guess we have to put up with the extra twins.
As you say, no right or wrong answers when it comes to flock management- horses for courses is what it is all about.