When I open a long document — just now Legge's bilingual Daodejing — I get this warning:
「Large File Edit
The current file is very large; editing it may cause Pleco to become slow and/ or unstable. Are you sure you want to continue?」
and when I edit, I immediately lose my place, usually flying to the beginning of the document.
Where fonts are concerned, all I'm really looking for is to have Latin and Chinese text in different sizes — when Chinese is big enough to read, the Latin characters are twice as large as they need to be. Looks clunky, and takes up to much of my screen.
A Closing Digression: in an age where any Apple, Facebook or Google customer is a voiceless chump, it's great to deal with the rare developers like Pleco who produce stellar software and give matching user support. Pleco 萬歲！