As turns out, we don't need Greasemonkey or Tampermonkey to adjust gurochan to our tastes. That is excessive. A simpler way to adjust the layout is using the extension called "Stylish" that provides an easy way to edit style sheets for any website. Here's a simple style sheet that I created and it seems to be improving my experience.

Perhaps some of these things could be considered for gurochan's built-in style sheets.

/* Expand the thread list to be wider and make it resizable */
.catalogtable {
resize:vertical;
width:90%;
margin-left:5%;
}
/* Prevent wrapping in the thread list */
.catataba {
white-space: nowrap;
}
/* Highlight the current row of the thread list under the mouse */
.catataba tr:hover {
background: #FFFFF0;
}
/* Limit the width of post bodies for easier reading, adjust to taste */
.body {
width:6in;
}
/* Prevent spans from wrapping */
form span {
white-space: nowrap;
}
/* Expand the width of the post entry form */
form table {
width:70%;
}
/* Right-align the left column and minimize the width */
th:first-child, td:first-child {
text-align:right;
width:0;
}
/* Expand the width of text and file fields */
form td input[type="text"], td input[type="file"] {
width:70%;
}