I agree with Michel ... that should be ample ...
I have 44/32/22 - 32-12 on my Trek and Thorn ... not too sure about my Giant though, but it feels pretty close.

I hardly use the big gears on my touring bikes when loaded touring, and I just coast down the hills more often than not ... after all, the idea of touring is to be able to look at the scenery rather than be head down and have it blur past, might as well go be car then!