Agreed. For pear tree branches that have bark that is older, thicker, stiffer, and grayer, I stop at about 1" diameter or thereabouts. And that is only when the branch is actively growing new leaves and thus full of sap that lets the thick bark easily slip away from the core wood. Once the scion is inserted and thus pushes the 2 stiff flaps on either side of the vertical slit upward so they no longer have contact with the core wood, they will not be pulled downward to again make flawless contact with the core wood by wrapping tape tightly around them. Leaving an under-the-flap gap that new tissue will have to fill in. Or not. An opened up desk stapler can be used to firmly staple down both flaps parallel to the scion so that more of the 2 flaps' under surface will resume having flush contact with the core wood. The staples are too dinky to be pushed into harder wood like citrus, but they sure make pear tree bark flaps get snugged up to the thicker/older pear core wood much better than only using tape wrapping. ....Bark grafting on pomegranate branches that are 1" and older can also work OK, but the side of the r/s branch opposite the slit will usually die off to about a 2" "dead bark zone". But the scions on the other side still grow like crazy. Next time I topwork older poms, I will do a bark graft on 2 opposite sides of each branch to hopefully get a better result........When following Joe's practice of slicing very thin strips of very thin bark on the back side of the scions just prior to inserting the scions below the flaps and next to the core wood, I have a difficult time making the very thin slices w/o sometimes going too deep into the already-thin wood. So, instead of slicing, I hold the grafting knife perpendicular to the scion and lightly scrape away the hyper thin bark on both side edges of the scion's wedge point. Just like using a knife blade to scrape the skin off of carrots. No more gouges.....Hats off to Joe Real for his very helpful how-to tutorials.