I took two tension rods per skylight and took some scrap dark fabric and some scrap white shiny fabric. I first measured my skylights and made the length of the fabric the same as the window but added enough inches for a large hem on both sides of the curtain for the tension rod slots. (I should have been a little more generous in retrospect, but it works well enough.)
I sewed shiny white fabric on top in the direction that the curtain would be facing the outside to reflect the light.
The only inconvenience is still having to get up on the ladder to open or close them.