In reply to IainRUK:
I got a pair of Xpedition a few months ago, which look fairly similar, only for rougher terrains (they have toe crampons that do the job). Happy with them, generally good stuff, used mainly in the Pyrenees, a bit in the Peak. I think these would be comparable with MSR Lightnings, the Wilderness ones would be for more gentle terrain.
But definitely go for 30's (at least). I am 65 kg and have carried 20 kgs of equipment (a daughter and stuff if you need to know) - so around 190 lbs in total. 30's felt already a bit small in fresh snow. Alone with my normal equipment (170 lbs) they were absolutely fine on whatever I have tried them.