I think lots of sailors dont like sailing upwind.I suspect power-sailer owners don't sail upwind very much, but should you wish to try it, that centerboard needs to be all the way down if you want to get "close to the wind"..It's what gives your boat it's upwind "bite". If the centerboard is only half-way down, the center of resistance moves aft and the boat will have lee helm, not a good thing..
Sometime i like it and , after some tests, with 15 kn or more, my Mac sails better with half centerbord down.
Any sailing boat without a rigid keel cant sail less than 50° by the wind. May be the X performance,with his flat hull, is less than 50°. So i think is better a good speed than a cpl of degees less and a slow boat.
