Am renovating a master bathroom in an 80's home. There is currently one sink. I want to install 2 sinks. There is room on the existing cabinet.

What I would like to do is tee off the existing hot and cold water supply lines and connect both sinks. The existing supply lines each have a shutoff valve. Don't really want to remove sheet rock and redo existing in wall water lines.

The only drawback I can think of is will there be too little water supply if the faucets in both sinks are turned on simultaneously.

Any thoughts on my plan?