I only have four sheep, all of which are Z's. The first one (Daffodil) lambed twins without us knowing, I found the lambs in the field later that morning. All of my girls are shearlings so this is their first time, as well as ours. Daffodil has proved to be an excellent mother, very protective of her lambs; despite being super tame she won't let me very close any more! There did seem to be a few problems for the lambs finding the teats as they were hidden by a rather thick fleece but perseverance paid off and I've not had to interfere. They are all outside and doing well.
The second required assistance lambing as she had twins both coming at once (three feet and one head in the birth canal) and had laboured quite a long time so was rather exhausted by the time they were born. The one lamb died due to cord severance in utero but the ewe lamb survivor is very vigorous and whilst mum was taking ages to get back on her feet (took about an hour), she was racing around the field shouting her head off and trying to suckle our remaining pregnant ewes. Susie eventually got up and proceeded to run away so I shut them both in a pen overnight and they have since bonded fine and are both outside.
Both mums are very milky - Z's are a dairy breed so cope very well with twins and trips. Blacksheep has had several sets of quads this year I believe, although I'm assuming that she will have fostered some onto other ewes.