Explicit way to define fonts in the document

I have been trying to set up a poster using beamer. My problem is that the poster has very clear specifications: 24-point for paragraphs, 24-point for figure captions, 28-point for authors' names and 36-point for title.

This might be for my lack of knowledge (even though I have been using LaTeX for about 6 years), but I feel like this is one way that word is way better than LaTeX (and it pains me to say that), since with word I know exactly which font is used each part.

In latex not only I can only choose some pre-defined fonts for my document in \documentclass, but after I do that it's not explicit which fonts are what size. (Is the base font the font for the paragraph? Then what font is the title? And the Section headers?)

Beamer tries to solve this with the \setbeamerfont command, but I found that for some reason it doesn't work for every theme, so either it really doesn't work, or I'm using it wrong and it's a counter-intuitive command.

My question is: is there a way to define each font in your document explicitly, easily, and that works across classes? (So I don't have to learn a command for beamer, a command for reports, etc.)

Here's a MWE. In this example some definitions work and some don't. But most importantly I can't use these definitions with other classes, so they're not general.

\documentclass[final]{beamer}
\usepackage{beamerposter} % Use the beamerposter package for laying out the poster

% These work
\setbeamerfont{title}{family=\rmfamily,series=\bfseries,size={\fontsize{36}{32}}}
\setbeamerfont{block title}{family=\rmfamily,series=\bfseries,size={\fontsize{36}{32}}}
\setbeamerfont{author}{size={\fontsize{36}{32}}}
\setbeamerfont{date}{size={\fontsize{36}{32}}}
% These don't work
\setbeamerfont{normaltext}{family=\rmfamily,series=\bfseries,size={\fontsize{30}{32}}}
\setbeamerfont{block body}{family=\rmfamily,series=\bfseries,size={\fontsize{36}{32}}}

\title{Fake title for MWE} % Poster title
\author{Author 1 and Author 2} % Author(s)

\begin{document}
\maketitle

\begin{frame}
We introduce a package that makes data processing
significatly more efficient:
\begin{itemize}
\item Easy to use
\item Oopen-source
\end{itemize}

\end{frame} % End of the enclosing frame
\end{document}

• Please post a minimal, but compilable example (MWE). – TeXnician Nov 19 '17 at 17:43
• It's a general question. I don't see which MWE I could post to illustrate it better. I'll try to come up with something – TomCho Nov 19 '17 at 17:45
• You could post a MWE for a beamerposter pointing out where you want which size of text to be applied. – TeXnician Nov 19 '17 at 17:46
• @TeXnician I added some MWE. Hope that's what you had in mind. – TomCho Nov 19 '17 at 18:06
• Do you really need to use beamer? Are you willing to switch to LuaLaTeX? – user139954 Nov 19 '17 at 18:14

To answer for the % These don't work fonts:

• \setbeamerfont{normaltext}{family=\rmfamily,series=\bfseries,size={\fontsize{30}{32}}}

There is a missing space, it should be normal text and a little trick is necessary to use this template, namely \AtBeginDocument{\usebeamerfont{normal text}}

• \setbeamerfont{block body}{family=\rmfamily,series=\bfseries,size={\fontsize{36}{32}}} This command already works perfectly fine, but you are not using block but alertblock, so you'll need \setbeamerfont{block body alerted}{family=\rmfamily,series=\bfseries,size={\fontsize{36}{32}}}

\documentclass[final]{beamer}
\usepackage{beamerposter} % Use the beamerposter package for laying out the poster

% These work
\setbeamerfont{title}{family=\rmfamily,series=\bfseries,size={\fontsize{36}{32}}}
\setbeamerfont{block title}{family=\rmfamily,series=\bfseries,size={\fontsize{36}{32}}}
\setbeamerfont{author}{size={\fontsize{36}{32}}}
\setbeamerfont{date}{size={\fontsize{36}{32}}}
\setbeamerfont{block body}{family=\rmfamily,series=\bfseries,size={\fontsize{36}{32}}}
\setbeamerfont{normal text}{family=\rmfamily,series=\bfseries,size={\fontsize{30}{32}}}
\AtBeginDocument{\usebeamerfont{normal text}}

\title{Fake title for MWE} % Poster title
\author{Author 1 and Author 2} % Author(s)

\begin{document}
\begin{frame}
\maketitle
text