No progress in 36+ hours, I'd have intervened long ago.
In the part of the membrane that is visible, can you see blood vessels that look like those you saw while candling? If those have retracted, since it is a side pip, then the wait time should be over.
It should be safe to dampen the membrane and peel off the shell between the hole and the fat end of the egg, then open it up all around to the level of the hole. Work slowly and carefully, dampening the membrane as you go. When you are done, the larger end of the egg should be completely removed, and the chick should be partially exposed. Place the egg back in the incubator so that the chick's back is either to one side or to the top, not the bottom. This will help ensure that the chick's neck isn't pulled upside down when he untucks his head.
If at any time you find fresh blood in the membrane, stop immediately and continue to wait.
Allow the chick to push out of the shell when he's ready, but after this long he may be too exhausted to do so and you may need to prompt/assist just a little. If you see blood vessels or yolk near the thighs, again stop and wait.