Hi buttercupbetty,
Regarding your thought about using wool, I recently did a review of an amazing 3" wool topper here:
https://forum.mattressunderground.com/t/sleeptek-classic-2000-3-wool-topper-review
Especially since you’ve tried wool and like it and if you are still considering that route, I’d have no concerns at all recommending this…it’s a wonderful product.