I wouldn't take that "change after 3rd grade" thing too seriously -- I was in 5th or 6th grade when I decided to start writing in block caps like my mom and brother did, and it was 8th grade when I went to a different school and they taught serious cursive. I learned a whole new cursive there.
Just as a side note, I saw a lovely "life hack" the other day for pencil grips -- hold a folded or wadded tissue with the bottom two fingers (ring and pinky), and the rest of the fingers just fall into place on a pencil.

My DS11 is fast approaching the point where he will be forced to adapt his handwriting to the legible side or fail everything. Or become a doctor.