If you have a hydraulic cylinder on your backstay, it might be a good idea to protect the seal on top of the cylinder from sun exposure. Vickie told me once it was not uncommon that the lip seal on the cylinder had to be replaced due to UV damages.
I made a simple UV-sunshield for our cylinder, using a screw cap from a Coca-Cola bottle. There has to be 1-2 mm play between the screw cap and the cylinder shaft. If not, it will not stay down and protect the seal.
I did cut the cork on one side just to make it possible to slide it on to the shaft. It is easy, and cost nothing!
If you have hydraulic hoses to the furlers of the main sail or the genoa, it is a also a good idea to protect the hoses for UV-radiation.