My best results are usually with 4o-mini-high, o3 is sometimes pretty good
I personally don’t like the canvas. I prefer the output on the chat
And a lot of times I say: provide full code for this file, or provide drop-in replacement (when I don’t want to deal with all the diffs). But usually at around 300-400 lines of code, it starts getting bad and then I need to refactor to break stuff up into multiple files (unless I can focus on just one method inside a file)