That may depend on the illumination in the scene as well as the final look. I preflash in batches after I cut my paper to size but still need to use a lens filter if I'm shooting outdoors in clear sunny light.

Also worth mentioning if things get rough is bleaching before developing the paper negative, i.e. bleaching the latent image. I've only done it to see if it works, but it's not something I can do consistently.