Larry , answers are always best from those who don't have a F5 like me
However I do have a Pentax 35mm which while having some of the bells and whistles of the F5 is by comparison a more primitive beast.
Maybe I have been lucky but in B&W I have always had reasonable negs in aperture mode and relying on the camera's meter.
The F5's matric metering is probably the best there is so I think that you should be OK using that.
Mike