The 30% tensioning is (I am told) as much brain training as muscle exercise. It is not necessary and could be counter productive to apply full tension (when we could force out a squirt) at times when we apply stress e.g sitting, bending, sneezing etc. and so the idea is to make the 30% almost an involuntary action. Sounds reasonable to me and so I add it to my daily regime. I also was given some Pilates exercises during which I also apply the 30%.
Horses for courses maybe. We are none of us the same and I am sorely jealous of those who achieve continence comparatively very quickly after their catheter has been removed. Whilst I am, in truth, pleased for them, knowing that statistically some of us may never fully get there it does make me wonder if I will be amongst that group.