2 things to consider here, first of all if you keep your revs down to 3,000 (which I find sufficient for day to day driving) then you'll be O.K. Secondly, it's important not to put the engine under heavy load, ie hard acceleration from 30 in 6th gear or straining the engine in a high gear up a steep hill. By using 95 Ron you will be down something like 5% on power and 2-3% on fuel economy. Rather than drive around panicking when I can't get Super I simply put £20 of 95 Ron and then fill up when that's gone.
Pete