Since you can build multiple scavenger stations in the same settlement I was wondering if anyone has tried this and if having multiple assigned scavenger stations provides an increase in resources and junk over just having one assigned scavenger station? Basically, I am into really large builds at all my settlements and am trying to max out my farming if all resources, especially wood and steel.

Yes I have done this. Any unassigned settlers you have (who aren't food, guards, stand workers) will naturally find and place scrap and junk into your workshop. Using scavenging stations increases the yield for these items.

It's fairly minimal with just one or two stations so the best results are done by creating settlements that have just food growers and scrap stations. Also highlighting specific items to search for with the magnifying glass will put focus on your scroungers to find those above other items.