# Adjusting word space with letterspace in small caps [duplicate]

I'm trying to set up a nice letterspacing for the small caps of my main font. The problem arises because, by letterspacing, inter word spacing are somewhat less distinguishable from the inter-letter space. I'm posting an exaggerate MWE but mind that usually I use small caps in headers (it's a philosophy book I'm typesetting), and so titles are common to have 2-3 words.

\documentclass{article}
\usepackage{fontspec}
\usepackage{polyglossia}
\setmainlanguage{english}
\setmainfont{EB Garamond}[
%Contextuals={WordFinal},
%BoldFont={GaramondPremrPro-Smbd},
%UprightFont={GaramondPremrPro},
%ItalicFont={GaramondPremrPro-It},
Ligatures=TeX,
SmallCapsFeatures={%
LetterSpace=6,
Letters=SmallCaps
},
Numbers=OldStyle%,
%Kerning=Uppercase%
]
\usepackage{microtype}
\usepackage{lipsum}
\begin{document}
\textsc{this is enhanced text}.
\lipsum[1]
\end{document}


I tried using the WordSpace fontspec feature, but that is not good for me since it's global, and not limited to the small caps.

Here is an example:

\documentclass{article}
\usepackage{fontspec}
\usepackage{polyglossia}
\setmainlanguage{english}
\setmainfont{EB Garamond}[
%Contextuals={WordFinal},
%BoldFont={GaramondPremrPro-Smbd},
%UprightFont={GaramondPremrPro},
%ItalicFont={GaramondPremrPro-It},
Ligatures=TeX,
SmallCapsFeatures={%
LetterSpace=6,
Letters=SmallCaps,
WordSpace=2
},
Numbers=OldStyle%,
%Kerning=Uppercase%
]
\usepackage{microtype}
\usepackage{lipsum}
\begin{document}
\textsc{this is enhanced text}.
\lipsum[1]
\end{document}


What I'd like to have is a somewhat proportional adjusting of the wordspace to the letterspace, either manual or automatic, but limited to the small caps, possibly without defining a specific font and redefining textsc.

IMPORTANT NOTE: please mind that I use and have to use LuaLaTeX, thus XeLaTeX-specific solutions won't be much of help, while general ones and LuaLaTeX-specific ones are most welcome.