I have tried two options.
Silicon spray (messy to get right) brush or cloth better.
My preferred option, given winter is coming and roof is not going to be used much.
Red rubber grease. It is messy (best put on with your fingers) It will stay nicely on the seals, softens then nicely and will make sure no leaks.
You just have to remember that if you raise the roof. Keep anything away from the seals as it will stain.