Using a Wedge on the edge of a chair

I love stack sitting.  Finally I can find comfort when I'm working on the road.  I find that rolling up a bath towel and placing it on the edge my hotel room chair works well for stack sitting.  This feels good, so I assume it's O.k.  But I just want to make sure.  If I place the wedge back any, the front edge of the chair puts pressure on my hamstrings, which I think I want to avoid.  I'll try to attach photos of my setup.  Am I on the right track? Thanks!I love stack sitting.  Finally I can find comfort when I'm working on the road.  I find that rolling up a bath towel and placing it on the edge my hotel room chair works well for stack sitting.  This feels good, so I assume it's O.k.  But I just want to make sure.  If I place the wedge back any, the front edge of the chair puts pressure on my hamstrings, which I think I want to avoid.  I'll try to attach photos of my setup.  Am I on the right track?

Thanks!