Recently switched to Arione saddle's after borrowing one from a work colleague, but when I use the usual method of getting the saddle level (i.e. long straight edge straight across the length of the saddle and spirit level on top) it looks like the nose is pointing upwards as the middle of the saddle seems to dip very slightly. If I set the middle-nose section level, the back points upwards. Anyone know the right way? Should I use the spirit level straight down the saddle, or just from middle to nose?