Since Community Events became available I don’t believe we support that tutorial anymore, but have kept it in place as a reference and useful starting point for people who want to dip into code and integrate both plugins.
So I can understand your desire to use Gravity Forms over Community Events, but the work in bridging the two is really something you’ll need to undertake by yourself (or engage a developer/designer to assist you).
We can definitely leave this open and see if other members of the community can assist, though, and you may also find useful snippets and advice around the forum.
Sorry we can’t do more!