FYI, spoke with Healey Surgeons yesterday to find out if I could get new canceling tangs, and was told to try stretching the springs on the horseshoe shaped bar to add pressure to the return of the lever instead. I was told that the springs compress from use (makes sense) and that their experience is that it isn't the tangs, but the spring, that cause the lever to fail to cancel. I'm going to give it a try and will report back.
On another front, I ordered some MacGregor door seals yesterday as well. One issue is that he is charging more than it says on his website, and he tells me that he needs to correct the website. Personally, I wasn't thrilled about it, but if these seals work as well as he says they will, I'll live with it. I'll report back after they've arrived.
Edit: Also, he told me that originally the seal should extend toward the back of the car to the first tenex snap, and then should have a cap on the end. I've never seen this before. Does anybody have a photo of how this is supposed to look? Thanks.