GitHub Projects condensed-and-more-like-waffle.io view, used with Stylus and optionally https://github.com/StylishThemes/GitHub-Dark

github_projects_condensed.css

.project-columns-container {
    padding: 0px !important;
}
.project-column {
    border-radius: 0px !important;
    border-right-width: 0px !important;
    margin-right: 0px !important;
    min-width: 300px;
}
.card-octicon {
    top: 30px !important;
    right: 15px !important;
    left: unset;
}
.js-project-issue-details-container {
    padding-left: 8px !important;
}
.js-project-issue-details-container > small.text-gray {
    font-size: 0px !important;
}
.js-project-issue-details-container > small.text-gray > .js-issue-number {
    font-size: 12px !important;
}
.labels > button {
    font-size: 10px !important;
}
.issue-meta-section.task-progress {
    display: none !important;
}
a.js-project-card-issue-link {
    color: #404040 !important;
    font-weight: 400 !important;
}
a.js-project-card-issue-link:hover {
    text-decoration: none;
}
.js-project-column > div:first-child > div:first-child {
   text-align: center !important;
}
.js-project-column > div:first-child > div:first-child > h4 {
   font-size: 12pt !important;
    margin-top: 5px !important;
   margin-bottom: -5px !important;
}
.js-project-card-details-pane {
    width: 50% !important;
    margin: auto;
    position: absolute;
    left: 0px;
    margin-top: 30px;
    margin-bottom: 30px;
    z-index: 1
}
.js-project-columns {
    padding-right: 0px !important;
}
.project-issue-body-wrapper {
    max-height: none;
    overflow: visible;
}
button.Details-content--shown {
    display: none !important;
}

Use with rule "URL starts with" and https://github.com/orgs/<orgname>/projects/<projectid>

Or regexes for org and project boards, update <org name> with your org name to avoid applying it to all boards across github:

https://github.com/orgs/<org name>/projects/\d+\?fullscreen=true
https://github.com/<org name>/[^/]+/projects/\d+\?fullscreen=true