"Did you have the same experience?"Nope, I'm a classical player. I have (had?) FD in my right hand.
I am a former rock player and understand the techniques involved, and have given a lot of thought to FD. There are risk factors to getting FD, and fretting hand legato technique ticks many of the boxes. I have come across several players who got FD this way. The technique demand you 'fuse' a sequence of notes together and thus fuse your fingering, it demands LOTS of practice to get it right. With something like this, you have to take small steps over a long period of time. Try and get it quickly and you have:
tension + over practice + 'hyper control' + desensitisation. By the latter two I mean its a technique where you are virtually encouraging your fingers to act as one big blob with no individual discrimination and freedom.
"There seems to be a paradox in your suggesting the ring/pinky alternating exercises will be hard togther with the assertion that forcing control will make things worse. If things are hard then surely more effort (control) is required?"
No, and this is a key to recovery. LESS CONSCIOUS effort is required, and you are aiming for NO control. The moment you exert any force on a digit to get it to do what it doesn't want to, you are simply feeding your FD. This is what caused your condition in the first pllace, fixing your hand in position and hammering away (literally). You need to back off, not exert more force.
Learning to exert what fels like no control, to get under the FD threshold and allow the fingers to move freely, is how you recover. It is the basis of Faris' and Fabra's approach to helping peope recover, both well documented here and on youtube. It is hard to do this, and requires a huge mental effort.
