Why do you say the No23?
I find GHR excellent for strengthening the hams at the knee to help prevent injury at the end of the swing phase. And back hypers are a safe and very effective way of developing the hams at the hip and also whole posterior chain including outer knee flexion range.
I use the GHR bar method similar to Major described but fixed inbetween a door frame, wouldnt be without it. For the back hyper I bought my own since gyms now seem to only have the angled version which isnt as effective.