If it's too piquant, then you really have to watch the milk handling and use ultra fresh milk while all those fat globules are still in tact.
And of course, washing helps. You can also try to reduce the water content and have a drier cheese, and age a little cooler... say 48-50F.
Beyond that, it's breed and diet.
For the culture, you could try Danisco's Kazu to create a milder flavor profile, or use undefined strains, like what you find in Probat, or in one of the DL gouda-type mixes.