The best place to measure your bores for wear is in mid/center stroke.
When the piston is at mid-stroke, the crank angle is 90°. When the crank is at 90° you have the maximum side force on the piston, therefore that is the spot that should get the most wear.
I wold at least check the top, middle, and bottom of the stroke in the bore as a minimum to evaluate the bore wear...
Also parallel and perpendicular to the crank centerline and at 45° angles, for each level that you check.