I use a SD Light-year quite a bit for my high-mountain, possibility-of-changeable-weather hikes. I prefer a double wall tent in those conditions. I made a new rain-fly for it out of sil-nylon to save some ounces; it works pretty well and lets more light through in addition. I use the "vestibule" for water bottles mainly.

I am now trying to figure out how to extend the fly to give a bit more protected space for cooking; so far nothing really clever has come to mind. I will, on occasion, take along a 4' x 6', 3+ oz. sil-nylon tarp as a cooking fly if the weather looks ominous. If you don't mind the extra hassle of setting it up and the minor weight penalty, this is probably the better alternative.