This summer I've started using a variant graft. A problem with the bark flap graft is keeping all 3 layers properly aligned during the parafilm wrapping procedure. There's a tendency for one or two of the layers to shift to the side during wrapping.
The change is cutting the slipping bark on the rootstock in the shape of an inverted "L". That's a vertical incision as in a "T" bud, but the top horizontal cut only goes in one direction, but farther, hence inverted"L". A very flat and slender scion has the epidermis and a sliver of cambium removed from each of the 2 sides (just as previously). The knife used must be very sharp to provide smooth edges.
The prepared scion is inserted and pushed firmly under the bark flap, with the scion bud sticking out of the top of the horizontal cut, if desired. Wrapping should be from the attached side to the open cut to securely hold the scion within the bark.
I find I'm able to complete these grafts faster and have a more stable finished graft.
Within 3 weeks the success rate of this graft should be able to be evaluated.
Prepared scion, cambium exposed on both sides.
Inverted "L" cut in rootstock bark -don't cut into wood.
Scion tucked securely to the left side - awaiting wrapping.
Graft wrapping - note the rotation - from the attached side toward the cut side on the rootstock.