Sorry it was too late to warn you. 
When I was looking for a USB microscope I found this video comparing yours (sort of) and (now) mine. The Andonstar is much better but still not great for working.
I think you (I) will need a strong far-away lens (as the project in the OP) or either working distance or depth of field are too bad to work.
I know professionals use binocular microscopes for soldering but these are far too expensive for me as a hobby tool. Maybe one of my old SLR lenses will work with a webcam.