I cant think of any other suggestion woofgang, Used to us double-declutch myself, many years ago, drive an automatic now but when in a manual gearbox vehicle I still have the habit. It was supposed to save wear on the clutch, dont't know it it ever did but I only ever had to change 2 in my life so there may be something in it. Alperchino with syncromesh you shouldn't need it unless your clutch fails and then you will to avoid crashing your gears, You will find it gives a smoother ride when changing gear and your passengers wont bounce back and forth IF you get the revs right, it comes with practice.