I think it's 6 and 2 3's really. If you keep them in during the day, they will probably be out for more hours, but if you do turn them out at night, there is less sugar in the grasss, so less likely to be a danger. Obviously in during the day has the added bonus of gettign them out of the hot sun/flies etc.

Definitely muzzle her whenever turned out, even if she is in for part of the day. You don't say how big she is, but obviously restrict her hay intake when she is stabled. Depending on size, 1 or two slices a night, and if you put it in one haylege (small holed) net inside another one (so in two nets effectively) it'll take her longer ot eat. If you also soak it for an hour or so it'll help remove some of the goodness.

Can you tell I am used to dealing with big fat bloaters?!