I can only do them with at maximum a 5th between 1 and 4 (C-D-E-G) in both hands, but I can do them. The fact that I have figured out how to do them slowly even in my left hand without my third knuckle collapsing on the way down is a miracle.
The chief problem is that the hand is held in a somewhat “broken” line. The way that I have to reach across the harp with the left hand (but not the right) forces the long bones of the hand to not line up with the bones of the forearm, and that line apparently has to be kept straight for me to have any hope of managing this. If those tendons are off-true in even the slightest degree, it’s gone.
Of course since the right hand is around and up, with the body of the harp out of the way, it’s much easier there.
So what I did to get started was to put the harp on my left shoulder, where my left wrist and forearm were straight this time, and just went slowly and looked at my fingers to make sure that the third knuckle was behaving itself, going painfully slowly the whole way. This way, at least my left hand could learn that yes, you can do this.
Then, I lined the harp up perfectly straight along my sternum, right under my chin (not too comfortable), and did it with both hands, so that I could make sure that the hands were absolutely symmetrical.
Then, slowly, I slid the harp back over onto my right shoulder and just kept going, maintaining the same straight wrist and straight back of the hand relative to the forearm bones. (Dorothy Taubman used to talk about the “broken arm” when it comes to piano technique, and it’s a problem there, too.)
So I can manage it now. Slowly, slowly. But it’s more than I could do before, so now I do a bit of it every single night until it feels recognizable to me, and to my hand. I’m constantly trying to move 2, 3, and 4 further down along the string as well, within reason. That seems to help things; I don’t want to “grimper la harpe” as Catherine Michel once noted a student doing in a masterclass online. But I don’t want to push them down to the point where I’m putting stress on them, either. I move my fingertips down, but not to the point where that knuckle collapses or the 4th finger feels loose or as if it’s going to go out of joint.
And I can manage a slow C-E-G-C turnaround in my right hand, which stuns me! I keep having to remind myself that that was absolutely impossible until very, very recently when I get down about not being able to play the music that I’m hearing in my head on the harp. The sooner I get this sort of garbage sorted out, the sooner I can start on that.
I just have to not do anything stupid like go crazy on it to the point where I hurt myself. I’m going for some time at nights now, but I’m also stopping when my hand(s) feel(s) tired.
Still, it’s as if I’ve been banging away at a brick wall, and I’m finally starting to see even the slightest hint of a crack. It’s heartening. It’s only the first of many walls, but it’s nice to bash through something.