The 50mmm gap at the bottom of your tent roughly matches the gap at the bottom-back of the 'mid I use. The tie-outs default to about 3", so basically 50mm. I never get condensation.

The 950mm pole height is pretty low. However, the wonderful thing about levitating your tent is that adjustable guylines and poles can change the height instantly for different weather conditions.

It may be a good idea to build a prototype out of tape and cardboard to see if you can move around enough and find out how it will make you feel. I found out the hard way that I don't like a fully enclosed bivy as my only shelter.