and the reason that the hone must have a perfect 45 degree cross hatch, is that 45 degrees is the decided standard so that all honing machines worldwide will leave a bore that doesn't spin the rings around during break in period. If we had more than 45 degrees, and one direction of the stroke of the hone had taken off more material than the other, then the friction of the rings on the walls, on the way down may be more than on the way up leading to the rings spinning and this would result in rings that never seat.
Any less than 45 and you would get chattering of the stones and an imperfect shape bore.
Thats about the basics of it.