OK, so you say you've used both context-free CVC words and also nonsense words. Which ones have you seen more of?
For DD5 (she turned 5 today!), only nonsense words helped appreciably. And we had to spend literally months on each pair she confused, without ANY context clues to whether it's a b or a d.
DD5 does all these things, too, by the way. I don't know if she's dyslexic or not, but I know we've remediated it successfully without needing any outside intervention. And it was hard work.