It depends very much on the material. I would however guess that if you use a very weak reducing agent (also that depends on the material, rather ascorbic acid instead of DMAB, just to take an example) you can probably live with a "high" salt-concentration, but I wouldnt overdo it and rather stick to a lower salt cencentration. But, the redicing agent is more important for the outcome I assume. Hope this helps :)

Per