Lady is 6′ 3″ is asking for LTech Hybrid H5. Her 5 iron is 40.5. Following tip trim instructions for LTech medium Ladies flex shaft, I believe that I would need to add an extender that’s about 1.5″ for a club length of 40.5″.
My recommendation is to add a graphite extender not to exceed 1″. Does that make any design sense in terms of closely maintaining correct shaft flex?
Adding the extension will not effect the shaft flex. If she is athletic with a little higher clubhead speed you might consider the L-Tech in the A flex. The medium L flex is fine, just thinking at her height and club length her club head speed might be a little higher than average. Again, I wouldn’t worry about using an extension. It will not effect the shafts playability.