Well, I think the rings are working out great. I just finished day 2 and it seems challenging, but less so than pull ups. I discovered that if I rest my feet on the futon inside the bedroom, I can do pull ups from a 180 degree angle (flat on my back, pulling straight up). It's harder than doing it from a smaller angle, so I imagine it's better for me. I don't know if I'll be able to sustain that angle on Friday, but it's worth a shot.