I recently bumped my hoist by 3 feet similar to what a lot of J/29 FR do. Still saving up for the bigger kite. Our masts are like tree trunks up to the headstay and then still pretty strong in the first few feet of taper. I haven't really worried about it, but no I wouldn't do a lot of hard reaching with a mast head kite.
I have found that above 8-10 kts of wind the boat speed is just as good reaching with a big headsail. I do want to get a used asym that I can fly off the pole for reaching.
