I have also found the Dulciana to be most useful in this respect. There are some beautiful examples to be found. What a pity that they have become unfashionable to some people. I think that an unenclosed Dulciana provides a wonderful alternative to the enclosed Salicional /Celeste effect in the Swell.
I have also played some wonderful organs in Stockholm with a wide variety of strings, some mild, some big and French. The 3 - manual romantic organ in the St Maria Magdelena Church has no less than 5 strings on manual III, including a Salicet at 4' pitch. One could sit and improvise all day!
