Align sans-serif text with TikZ

Consider the following MWE

documentclass{standalone}
usepackage{tikz}
usetikzlibrary{positioning}

begin{document}
begin{tikzpicture}

node[anchor=west, inner sep=0pt, draw, very thin, rectangle] (a) at (0,0) {scalebox{15}{sffamily LARGE}};

node[anchor=west, inner sep=0pt, draw, very thin, rectangle] (b) at (0,-4) {scalebox{3}{sffamily smaller text}};

draw[blue] (a.west) ++ (0,-2cm) -- ++(0,4cm);
draw[red] (a.west) ++ (-0.2cm,0) -- ++(0.4cm,0);
draw[red] (a.west) ++ (0,-0.2cm) -- ++(0,0.4cm);

draw[blue] (b.west) ++ (0,-2cm) -- ++(0,4cm);
draw[red] (b.west) ++ (-0.2cm,0) -- ++(0.4cm,0);
draw[red] (b.west) ++ (0,-0.2cm) -- ++(0,0.4cm);

end{tikzpicture}
end{document}

which produces this result:

Why is there some space between the "bounding box" and the letter L? I want to remove the white space around the text exactly, such that the vertical line of the L and the smaller text below align perfectly.

Further, I want to scale the smaller text such that it becomes exactly as wide as the top text. How is that possible?

documentclass{article}
usepackage{tikz}
usepackage[showframe]{geometry}
parindent=0pt
begin{document}

fontsize{1cm}{1.3cm}selectfont sffamily
LARGE

TEST

XXX

tikz[overlay]draw[red](0,0)--++(0,5);
end{document}