When I said that your size could be the maximum for Helix, its about the reach that I was talking since your saddle is pushed as much as possible to the rear and you already needed an extension on the stem.

I know the Helix geometry specs and the handlebar to saddle max of 713mm is not a lot on my Birdy 3 with the stem at the lowest position and the saddle in the middle of its rail I have 740mm.