> when a company logo links to the home page, an alt text of “Back to hone page” is probably more useful than “Company logo”

I've always used title in the anchor tag for that rather than the image alt text (title="back to the home page" in the anchor; and then alt="Company logo" in the img tag). That way you're properly describing what the image is and also providing information on where the associated link goes.

Can anyone here with experience with screen readers clarify if that's an effective approach?