If you're going back country touring with 26" rims, you should probably make provision to fit a cheap and nasty MTB tyre in case of emergency, since that's want you're likely to be able to find anywhere. In that case, your clearances should allow for knobbly 26x2.0 at least. It's no good having a set up which only works with the kind of tyres you can only get in a well stocked European boutique.
If you're going back country touring with 26" rims, you should probably make provision to fit a cheap and nasty MTB tyre in case of emergency, since that's want you're likely to be able to find anywhere. In that case, your clearances should allow for knobbly 26x2.0 at least. It's no good having a set up which only works with the kind of tyres you can only get in a well stocked European boutique.