I almost exclusively use the dichroic enlarger head for B&W printing because I prefer the diffuse light source. Others prefer a more traditional B&W head as there is a sense of increased sharpness. Whether you use a dichroic head for grade selection is a matter of logistical choice, but one must recognize that the dichroic head produces a print with substantial differences in print asthetics. I even modified my B&W head with diffusion to soften the grain and minimize scratches on the negs.