Hi Stu!
My back is great and apparently as long as I keep my back in a vertical position I can handle a good amount of weight with no pain whatsoever. I am able to do split squats with 100 kg and I feel great. I have also started to do one-arm pull ups with 15kg and one-arm inverted rows.
I am playing rugby in New Zealand at the moment and even though I weigh only 82 kg I feel strong and very capable of tackling 100 kg adversaries applying your techniques.
Take care my friend and thanks again for everything.