30" (vanity width) - 20" (mirror width) / 2 = 5" (distance from mirror to wall).

Even these narrow lights (WAC Lighting Turbo 14 in. Wall Sconce, Kohler Purist 1-Light Polished Chrome Wall Sconce) are 5" wide so they'll look like they're jammed in between the mirror and the wall. I'd put lights above the mirrors.

-- amateur

We also have the 3” pullout which gives another 1” to wall and can move sinks slightly to get to 7”. We found many with 4.5” plates. You still think that isn’t enough space?

How wide are the sinks?

16” wide rectangles

Assume sinks are moved inward 1" from adjacent walls.

• Distance between outside edges of sinks and walls is 8"
• Distance between outside edges of 20" mirrors and walls is 6"
• Distance between outside edges of mirror and center lines of sconces is 3"
• Distance between sinks is ( ( 30 - 16 ) /2 - 1 ) x 2 + 3 = 15"
• Distance between mirrors is 15 - 2 - 2 = 11"
• Distance between inside edges of mirrors and center line of sconce is 11 / 2 = 5-1/2"

So the center line of the two outside sconces would 3" from the mirror but the center line of the middle sconce would be 5-1/2" from the mirrors. I think this would appear unbalanced.

I was thinking of making it 7.5" on each side which would make it 7" in middle. What do you think? I really appreciate you looking at this. We really want the 3 sconces, but want confirmation that it will look OK (or if you don't think it will, we may have to rethink).

Too late.
Already ordered Robern cabinets.
Not returnable.