How can I position some text on the same place on multiple pages with partly different content?

Question

I am creating the first pages of a book and I want one page with just the title and the next page to have title plus the authors and some other stuff. However LaTeX places the title differently on the pages because of the other text on the second page which is not on the first page. How can I make the title go at exactly the same location on both pages?

Here is an example of what I mean:

\documentclass[10pt,twoside,titlepage]{book}
\begin{document}

\pagestyle{empty}
\vspace*{0.3 \textheight}
\LARGE
\noindent
\textsf{bla bla}

\huge
\textsf{\textbf{Bla Vla Bla}} \\

\cleardoublepage

\vspace*{0.3 \textheight}
\LARGE
\noindent
\textsf{bla bla}

\huge
\textsf{\textbf{Bla Vla Bla}} \\
\normalsize

\noindent
\begin{flushright}
\begin{minipage}{0.4\textwidth}
Author 1 \\
Author 2 \\
Author 3 \\
\end{minipage}
\end{flushright}

\end{document}

Answer 1

You probably mean the different line spacing between "Bla Bla" and "Bla Vla Bla". This caused by the \normalsize command on the second page. It is in the same paragraph as the text before and so affects its \baselineskip. Put an empty line before the \normalsize. And remove this senseless \\.