A question for all baritone players playing a Sovereign baritone. How do you find the valve action? My valves are so c**p...the action is soooo heavy. Our other baritone in the band is the same so I guess it's a common problem. I've tried cleaning them, oiling them more and even rubbing them with very very fine wet and dry paper all to no avail. I've been advised to change the springs to tenor horn ones. Anyone have any experience of this? Does it do any good?