[KevinH]

And I just tested it on macOS (installing it only for my user and not system installed) and it worked just fine giving lots of space between lines.

So BeckyEbook's code (even in its early versions) has clearly demonstrated that we could use a python3 program to allow the user to scale the line spacing as needed in their preferred monospaced ttf font.

If fontTool is pure python, we may be able to include it in a Sigil plugin and have the plugin do the work.

So this is probably an approach that will work for those few who need or want more linespacing without hurting Sigil's performance esecially on large text files.

Nicely Done BeckyEbook!