[Tex/LaTex] Redefine mathematical symbols in size

Question

I just figured out, that the greater equal symbol, \geq, don't look as I want it to look when I print my document. Because I used it very often, I want to redefine the \geq command resulting in another version.

Firstly it is to big. I found the package scalerel and managed to scale it and redefine it:

\let\oldgeq\geq
\renewcommand{\geq}{\scaleobj{0.8}{\oldgeq}}

That works fine, the spaces are too small, but that's not the point here.

Secondly, the bottom line of the symbol is not aligned with the rest of the text. It' a bit below the rest if you look closely. So I tried to align it or set it a little over the textline, but it didn't work. I found a work-around with tikz, but then it only fits in the right place in normalfont. I want it to align with the text in every fontsize, so this isn't a good solution.

Maybe someone can help me with my second problem or have an even better solution for the whole problem?

Here is a MWE:

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{scalerel}

\let\oldgeq\geq
\renewcommand{\geq}{\scaleobj{0.8}{\oldgeq}}

\begin{document}
$5\oldgeq8$ $5\geq8$
\end{document}

Thanks in advance.

Answer 1

I'm not sure what you dislike about the standard symbol. Anyway, you can and should use \mathpalette.

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{graphicx}

\let\oldgeq\geq
\let\oldleq\leq
\renewcommand{\geq}{\mathrel{\mathpalette\bueckirel\oldgeq}}
\renewcommand{\leq}{\mathrel{\mathpalette\bueckirel\oldleq}}
\newcommand{\bueckirel}[2]{%
  \raisebox{\depth}{\scalebox{0.8}{$#1#2$}}%
}

\begin{document}

$5\oldgeq8$ $5\geq8_{a\geq b}$

$5\oldleq8$ $5\leq8_{a\leq b}$

\end{document}