10 inch long legs for the Furinno "Turn-N-Tube" end table in order to raise the height up a bit more. You can see in my photo I added them at the bottom and added another shelf of heavier material to keep the table stable and weighted down

Printed at .3 height and 30% infill but bump that up based on how much weight you need to support. On this extra length would suggest adding another shelf (before attaching the feet) for extra rigidity. Just take the shelf it comes with to use as a template to cut out from a piece of real wood.

BONUS since the diameter of these are a little thinner than the ones that come with it (or if you want to save material and print them a little thinner), you can even slide them inside of 1.25" PVC pipes for super strength, tho the shelf max weight are rated to only be 30lbs so that might be overkill.