The right tip radius gives consistent contact without sharp edges. Shape only after the adhesive has cured, using fine abrasive and light pressure.
Sequence
Level the sides flush with the shaft first, then round the crown without cutting leather beside the ferrule. The edge should be smooth, not tapered away into the shaft.
Check the result
Feel around the edge, apply chalk and hit several soft shots. If the tip slips or has a burr, stop playing and refine the shape.