I am on Tahoe 26.1. In Apple Mail, my default font for messages is set at Times New Roman 20, as it has been for several years. I still get that as the initial font size, when I start to reply to a message. However, previously I was able to copy material from messages quoted below my reply, and change their font size to 20 in my message text, or indeed to select all the quoted messages and change their font size to 20. But to my surprise the font size 20 is no longer available in the drop-down font size menu - it has 14, 18 and 24, but no intervening sizes such as 20.
Can someone tell me how to change font size of quoted text to 20? 18 is just a bit too small for me, and 24 is considerably too large! dialabrain seems to be suggesting that I can overwrite the fixed font sizes in the drop-down menu, but I am unable to do that.