I'm laying sheet vinyl directly over concrete in a basement bathroom. The rest of the basement is bare concrete. Do I just glue down the edge really well where the vinyl ends? I found an "Armstrong 1/8" VCT to Nothing Reducer VT525" online. it looks like this would just be glued down to the concrete right next to the end of the vinyl. Is that the right transition for this application? Lowes has a similar looking "FLEXCO Reducer 1-in x 36-in Cappuccino Vinyl Reducers Floor Transition Strip" Thanks.
Floor transition trims (or strips) are usually glued. I would avoid an anchor, because in this case it's not really a transition (it's just vinyl on concrete, so it's less than 1mm) and the anchor head (no matter how flat) will not be flush; it'll look bad, and could lead to tripping.
The thing is that the smallets trims expect some height difference. Perhaps you can use a carpet trim, that's fastened with nails (and is flatter).
I strongly recommend a vinyl strip (or metal threshold) to protect the sheet vinyl edge.
No matter how well you glue the edge down to the concrete, someone will catch the sheet vinyl edge with their shoe and pull it loose.