For a 48-inch vanity, I would keep it simple: one larger mirror centered on the sink, rather than two mirrors. Two mirrors only really work with two sinks — on a 48" single vanity they chop the wall up and neither one lines up with the faucet.

Practical sizing and mounting:
1. Mirror width about 42-44 inches max — a few inches narrower than the vanity on each side. Bottom edge about 5-6 inches above the faucet/backsplash top, and center it on the faucet, not just on the wall.
2. Sconces give the best light on your face, because light from both sides has fewer shadows than a bar overhead, which casts shadows under eyes and chin. Mount sconce centers roughly 65-70 inches from the floor (about eye level) and, if the wall allows it, 36-40 inches apart centered on the sink. On a tight 48" wall that can get crowded, which is the one case where an LED mirror makes sense.
3. If you go LED mirror: choose 3000K (warm, flattering — avoid 5000K+ daylight in a bathroom), CRI 90+, dimmable, and ideally with a defogger. Check how it is controlled before you buy — some only work from a touch button on the glass, some can be wired to a wall switch, and remember if the built-in light ever fails you are usually replacing the whole mirror.
4. Whatever you choose, put the vanity light on a dimmer and keep all the bathroom lighting on the same color temperature so the tile and skin tones do not fight each other.

My pick for this size: one framed mirror in the same metal finish as your faucets, plus a pair of slim sconces if you have the width — or a good 3000K LED mirror if you do not.