You also have to take into consideration the width, thickness and material. The width and thickness will give you the angle based on where the grind line starts. For example comparing the Full Flatt grind (spine to edge) to the saber grind (grind line starts at ~half of the width) the saber grind will leave slightly more material behind the edge when taken to zero.

I also mentioned material. The material has to be able to perform for the tools designed purpose. Hard metals tend to chip and soft metals tend to roll and deform when ground thin. There is a balancing act between metal and angle to achieve optimum performance for a given task. There is also a fourth consideration and that is lateral forces. When striking and object the forces are not always parallel to the edge but can also be perpendicular. Lateral (perpendicular) forces at the edge can be massive since they are concentrated on a very small area. The tool can perform perfectly under perfect parallel loading and fail with the slightest lateral load.