Besson New Standard - Valve Question

[ParLawGod]

Can anyone tell me if there are any major differences between the Besson New Standard valves and the Besson Sovereign valves.

I would like to improve the action (the valves are very good, but don't seem to be as quick as the Sovereigns I have played). I am interested in getting new springs...does anyone know if the older Besson springs are heavier, will it make a difference?

Also, I was wondering if anyone knows if new Besson valve buttons fit on New Standard euphoniums? I dislike the New Standard valve buttons (they are hard on the tips of my fingers to be honest) and much prefer the newer buttons.

Any information would be greatly appreciated.

Thanks!