I got it done at 35, it went pretty well and I was into work that night with an ice pack on my nuts. I booked it when I had a month of desk work instead of being on the floor doing lifting.
There was a small complication, I had swelling in one testes and had to go in a month later to get an anti-inflammatory injection directly into the ball, it is still a bit more large in the epididymis.
I think you mean the Geneva Checklist.