Would using thunderbolt-to-hdmi help?
Option+click Scaled

You can toggle between Apple’s easy-to-understand “Larger Text”–“More Space” icons mode and the other mode listing specific resolutions. To toggle, hold down the Option key while clicking Scaled radio button.





Retina

As for that comment “Don’t used scaled.” on the Question, that is wrong advice. Scaled options are Retina-style by default, more commonly known as HiDPI. Note the checkbox Show low resolution modes in the second screen shot above. Checking that box and choosing a resolution listed with the notation (low resolution) means you are disabling the Retina feature and scaling up the image crudely (wasting pixels).