With a bevel up plane it will affect the cutting angle, so it depends what wood and type of work is at hand.
The bed is 12 degrees, so if you want to end up with 45 degrees (the commonest angle of bench planes) then you would hone at 33 degrees or thereabout. Higher angles will suit difficult grain, but be harder to push and (in my view) loose their edge quicker. Lower angles will have more of a slicing action, but can cause tear out on tricky grain.
The beauty of the bevel up plane is that its easy to mess about with the angle of the blade to experiment, without masses of grinding because its only the final honing that counts anglewise.
Ed