This is going to sound negative but if you haven't got blacks and white highlights are you sure that your exposure and more importantly your grade is right?
I have used Cooltone and before that "normal" B&W developer( Nova Darkroom's own) and while the Cooltone paper in Cooltone developer was colder to look at than Ilford Multigrade in Nova developer it didn't really make the blacks blacker and the whites whiter. An overall greyness strongly suggests that the contrast grade is too low.
My paper was RC and not FB but that shouldn't make a difference. Otherwise switching to RC would cure the problem and few would use FB paper.
Might help if you attach a print that you are not satisfied with.