In reply to Nemo9:
Definitely book ahead. At least you're not going at Easter, when it will be really busy, it's still likely to be fairly busy.
Bill O'Connor's book is great for ideas and inspiration, some of the days/ routes can be optimistic for even fairly fit folk. But it's not vital (though if you're newish to touring then the intro chapter on route planning/ travel in avalanche terrain etc may be useful)
What is very useful is the Swiss LK 1:50000 map with ski route overlay (and including grades, cautions, short narrative, hut & public transport info printed on the back). Although the Austrian/ German Alpine club maps [DAV] (at 1:25k) will have ski routes (if you get the winter rather than summer version), they're not always up to date which can makes a big difference on Austrian glaciers that have retreated significantly in recent years. More, the DAV maps don't give route grades or any narrative info. Because Silvretta is right on the border, I think all of that tour (IIRC) can be done using LKS maps. So with the Tarasp sheet (and possibly Arlberg) you really would have enough info not to bother with O'Connor's book. If you're not aware of it, then
http://map.schweizmobil.ch/?lang=en is a great resource for plotting.
Oh, and re. Craigloon's point about getting to Jamtal hut - you can also get there by using the lifts to one of the top stations above Ischgl, then skiing down to Zeblasjoch, and a short skin then another fun descent right to the hut. much better than slogging up the long gentle incline of the valley track.
Lots of fun days out around Silvretta. The Tuoi hut, just across into Switzerland from either Jamtal or Wiesbadner huts, is lovely. great custodian and fab food.
have fun.