[KevinH]

It is strange. It would not slow down QPlainTextEdit at all to add a user settable but fixed amount to the lineHeight to create better text spacing.

That said, from the qfontengine code we now know the exact values to change in a font to make the line gap (leading value) larger.

Perhaps a python program could allow a user to select a monospaced font and then update the type linegap, and leading value (hhea table leading value on mac) to created a modified font for them.

There are some nice font tools in python. That might be an avenue to consider.