I cut one up today. I consider it a failed effort for me. I am 275 lbs and can get the stepps solid on the trees. When I tried this platform on a stepp, neither running the rope under the holes or over the holes allowed for the solid cam lock on the tree. I did get it to have a "weak" cam lock, but the top standoffs would pull away from the tree.
If you look at a stepp solidly set on the tree, the rope goes where the plywood sits. Either over or below the plywood, it is just not getting the proper cam lock for me. Maybe for you light guys, it'll be acceptable, but it doesn't work for me.
Andrew @SteppsbyWildEdge, please let us all know when you have a platform!
I use the stepps w/ a guidos web, and sit without needing a comfortable platform (sitter, not a leaner). Waiting on the kestrel and looking to enhance the platform to be comfortable for a leaner.
That is my 2 cents. Don't let my outcome dissuade you from trying this. Just be forewarned if you are on the bigger side weight wise.