I think most people already do use 20-50. I use it myself, and the same type as you, Vtwin. Valvoline also makes a bike oil that is NOT synth, but it's even quieter than Vtwin. I tried it and it did quiet the engine down, especially when cold where i'd say it was a good 50-60% quieter. But it will cost you in terms of power. I lost a fair bit of accelleration and therefore went back to Vtwin a week later.
