Vihuela string heights

[Christopher Allworth]

I would very much like to know the ideal string heights from the fingerboard of a vihuela since my fingers feel as if they are trudging instead of alighting.

Many thanks

[Bill Brettschneider]

As close as possible before buzzing? 

[Bill Brettschneider]

I should have added that the condition of the neck (straight/relief) will have be a factor in how low the strings can be