[JSWolf]

Originally Posted by enuddleyarbl

On my system, a "first time" open of that book (one without a delay) in the viewer takes 7 seconds.

EDIT: In case you're wondering, here's the CSS I'm using in the book (the only things that aren't normal for me are the last two "table" type classes):

@page {
  margin-top: 0;
  margin-left: 0;
  margin-right: 0;
  margin-bottom: 0;
}
body, html {
  /* Basic Styling for HTML and BODY Sections of a File */
  border-width: 0;
  height: 100%;
  margin: 0;
  orphans: 1;
  padding: 0;
  widows: 1;
}
h1, h2 {
  /* Basic Chapter Heading Stlying */
  margin-top: 0.7em;
  margin-bottom: 0.7em;
  page-break-before: always;
  page-break-after: avoid;
  text-align: center;
}
h1 + p, h2 + p, hr + p, .note + p, .placard + p, .song + p {
  /* Non-indented Paragraphs Styling (for paragraphs that follow something and shouldn't be indented) */
  text-indent: 0;
}
h1 + p::first-letter, h2 + p::first-letter, hr + p::first-letter {
  /* First-Letter Styling (for the first letter following certain things (IOW, dropcaps)) */
  font-weight: bold;
}
hr {
  /* Thematic break to use 3 asterisks between parts of story */
  margin-top: 0.9em;
  margin-bottom: 0.9em;
  border: none;
}
hr::before {
  content: "***";
  display: block;
  text-align: center;
}
p {
  /* Basic paragraph styling */
  display: block;
  margin-top: 0;
  margin-bottom: 1;
  text-indent: 1.2em;
}
/* */
/* This whole section is styling for specific page types of a book */
/* */
div.aboutauthorpage p {
  /* About the Author Page Styling */
  margin-left: 5%;
  margin-right: 5%;
}
div.titlepage p {
  text-align: center;
  text-indent: 0;
}
div.acknowledgmentspage p {
  /* Acknowledgments Page Styling */
  margin-left: 5%;
  margin-right: 5%;
  text-align: center;
  text-indent: 0;
}
div.alsobypage p {
  /* Also By Page Styling */
  font-size: small;
  margin-left: 5%;
  margin-right: 5%;
  text-align: center;
  text-indent: 0;
}
div.copyrightpage p {
  /* Copyright Page Styling */
  font-size: small;
  margin-bottom: 0.5em;
  text-align: center;
  text-indent: 0;
}
div.dedicationpage p {
  /* Dedication Page Styling */
  font-size: 90%;
  font-style: italic;
  margin-left: 5%;
  margin-right: 5%;
  text-align: center;
  text-indent: 0;
}
div.epigraphpage p.signature, .signature {
  margin-bottom: 0.5em;
  margin-top: 0.5em;
  text-align: right;
}
div.epigraphpage p {
  /* Epigraph Page Styling */
  font-size: small;
  margin-left: 15%;
  margin-right: 15%;
  text-indent: 0;
}
/* */
/* This is a section for types of chunks on a page */
/* */
div.note {
  /* Letter Styling */
  display: block;
  font-size: 0.88em;
  margin-left: 2em;
  margin-right: 2em;
  text-align: left;
}
div.note p {
  margin-bottom: 1em;
  margin-top: 1em;
  text-indent: 0;
}
div.song {
  /* Song Styling */
  display: block;
  font-size: 0.88em;
  font-style: italic;
  font-weight: bold;
  margin-left: 2em;
  margin-right: 2em;
}
div.song p {
  padding-left: 3em;
  text-indent: -3em;
  text-align: left;
}
/* */
/* A styling section for things that apply everywhere */
/* */
.placard {
  /* Styling for a placard or headline */
  font-size: 0.88em;
  font-weight: bold;
  margin-bottom: 2em;
  margin-top: 2em;
  text-align: center;
  text-indent: 0;
}
.smallcaps {
  /* Smallcaps styling (text should be typed normally and will be smallcapped) */
  font-variant: small-caps;
}
table#table001 {
  table-layout: fixed;
  width: 100%;
  border-collapse: separate;
  border-spacing: 5px;
  border: 1px black solid;
}
table#table001 td {
  width: 50%;
  border: 0;
  padding: 2px;
}

Your 7 second opening was with modified CSS. Mine was as is. Either way, any time under 1 minute is OK with me.