If I read correctly, you didn't say the porch was not level, you just wanted to bring it up by 1 1/4". If that's the case, I would use Durock over thin set on your base layer, then finish with a wood figured tile on thinset on top of the Durock. Follow Durock installation instructions with regards to gapping, tapping, etc. Work out the thickness' of all materials. Done this way, you will have two layers of thinset you can manipulate to achieve the exact height you want. Or, if you want a floating floor, then increase the initial layer of thinset.