I haven't put any added cover protection over my skylights..., but I do apply Aerospace 303 a couple times a year for UV protection, thus minimizing yellowing and becoming brittle (little help for hail).
On the inside I use the two-sided-foil attached with velcro....., the same sun-shield cover sold for the entry door window.
This product:
https://www.amazon.com/Camco-SunShie.../dp/B001D9E41I
I also removed the interior ceiling skylight covers and added an insulation barrier (stapled two sided insulation foil) in any open area around the wood trusses, this reduced the amount of condensation buildup on the skylights during cold weather camping.
Bob
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2016 GM 2500HD 6.0L/4.10
2018 Jay Flight 24RBS
2002 GM 2500HD 6.0L/4:10 (retired)
2005 Jayco Eagle 278FBS (retired)
1999 Jayco Eagle 246FB (retired)
Reese HP Dual Cam (Strait-Line)