draw[Ruler] How to have ifnumn=XYZ to be drawn longer or shorter

Please consider the following code:

% Y-ruler
newcommandyRuler[5]{
path let p1=($(#1)-(#2)$) in 
pgfextra{ pgfmathsetlengthmacro{RasterboxesHeight}{veclen(x1,y1)} } 
[savevalue={h}{RasterboxesHeight}];
pgfmathsetmacroNoYdiv{h/u} % Number of y divisions

draw[Ruler] (#1) coordinate(Y) -- (#2);
foreach n in {0,1,...,NoYdiv}{%%
draw[Ruler] ([yshift=n*u]Y) -- +(#4,0) node[#3, inner sep=1pt]{
ifnumn=1 n,cm else nfi};
}%%
foreach n in {0.1,0.2,...,NoYdiv}{%% 
draw[] ([yshift=n*u]Y) -- +(#5,0);
}%%
}

Which outputs something as such (there are 2 Y-rulers in this case):

yRuler{LLM}{ULM}{right}{4mm}{2mm}
yRuler{LRM}{URM}{left}{-4mm}{-2mm}

As one can see, the 1cm already overlaps perfectly.

It would be great if also the 0s below them could overlap perfectly, as well as the 2s and the 3s above.

How could we adapt the code above to achieve this result? That is, make the draw[Ruler] have longer strokes for all numbers other than 1?

Don’t worry about the exact yshift needed, as long as you can input some variable to play with, I will be very happy.

documentclass[margin=5pt, tikz]{standalone}
usepackage{tikz}
begin{document}
begin{tikzpicture}[]
foreach n in {1,...,5}{
ifnumn=3  draw[yshift=-n cm, red] (0,0) -- (4,0) node[right]{n};
else draw[yshift=-n cm] (0,0) -- (2,0) node[right]{ifnumn=1 n~(it's one) else nfi};
fi}
end{tikzpicture}
end{document}