Good advice, I wish more VN developers would follow these guide lines.
Worst few cases I see too often, are where they put the text over the whole width or even worse completely on the left/right side and only using <30% of the width of the screen. Making reading the text awkward.
I even have modified some VNs (for myself) to improve readability by changing fonts, text-box widths. Lucky that is often easy doable with Ren'Py based VNs. (If you are some what handy with Ren'Py)