Two sinks is a scheduling decision before it is a design one. The design has to catch up afterward.
Width is the problem. Past 60 inches a vanity stops reading as an object in the room and starts reading as a wall, and the mid-century answer has always been to get the mass off the floor. That instinct, raise it or lighten it, runs through all the mid century modern design that still looks right decades on.
Most double sink vanities are chosen on width alone. Choose this one on what sits under it and between the bowls, then match the wood to the rest of the mid-century modern bathroom furniture in the room rather than to the tile.
Sixty or seventy-two: sizing an MCM double vanity
Sixty is the compromise size and deserves a hard look. Two sinks in a 60 inch mid century modern bathroom vanity leave each person about eight inches of counter and put the two of you close enough to bump elbows. It solves the morning and nothing else. A 72 inch double vanity is where the format starts to feel generous: real surface outboard of each bowl, a drawer bank you can use, and enough distance between the faucets that the mirrors above can be two rather than one long sheet.
If the wall will not take 72, the honest move is often to stop. A wide cabinet with one offset sink gives you more usable counter than a cramped double and looks better doing it.
The middle is where a double sink vanity goes wrong
The dead zone between the bowls
Between two sinks sits a strip of counter nobody owns. On the good designs it is deliberate, sized for a tray or a stone bowl, with full depth drawers below it. On the bad ones it is whatever was left over, eleven inches of nothing above a false drawer front. Measure it before you order.
Drawers against plumbing on a mid century modern double bathroom vanity
Two sinks means two P-traps, and they land exactly where the drawer boxes want to be. Most well-made cabinets solve this with a central bank of real drawers flanked by doors. That is the right compromise. Be suspicious of any 72 inch design claiming full width drawers across all three sections.
Getting the weight off the floor
A 72 inch mid century modern walnut bathroom vanity is a lot of dark mass in a room that is otherwise hard and cool. Tapered legs are the traditional fix and still the best one, because visible floor under a long cabinet reads as lightness even when the piece is heavy. A floating carcass does the same more emphatically and asks for real blocking. Either beats a plinth, which takes a long cabinet and sets it down like a crate.
What wood does across 72 inches
Whatever the grain does, it does twice as much at this width. Walnut goes noticeably redder under warm evening bulbs, and on a long top you read that shift across the whole run rather than in a single panel. White oak holds steadier and is the safer choice on a wide mid century bath vanity. Acacia is the most active of the three, which lands as character on a 36 inch cabinet and as noise on a 72.
When a double sink is the wrong call
If the master bathroom has under about nine feet of clear wall, if only one of you is ever getting ready at that hour, or if you want the room to feel larger than it is, the second sink costs more than it returns. Plenty of double bowl vanities get bought for resale rather than for use, and it shows.
A good one earns the width. It gives each person a real surface, keeps the floor visible, and still looks like something somebody designed rather than something that had to fit.