Ok now that I am pretty much done I want to put up my call and templates in case it helps others.
The templates for the chunks I used started out directly from the getrelated documentation page (
http://rtfm.modx.com/display/ADDON/getRelated), which was really convenient, but the call I had to cobble from some different sources, mostly this thread.
My html and call are:
<div class="related">
[[getRelated? &tplOuter=`getrelated_tplOuter` &tplRow=`getrelated_tplRow` &fields=`longtitle:6,pagetitle:4,introtext:2` &parents=`216` &parentsDepth=`6`]]
</div>
The div is perhaps unnecessary but I wanted to be able to style it. But actually most of the styling comes from the ul class rather than the div. I hope I am targeting the right info from my pages, as we focus on the long title generally.
I changed some values in the snippet itself instead of modifying them in the call, for instance I set the limit to 6 in the snippet directly rather than adding a value in the call of &limit. And I learned that you definitely need a ? after getRelated, or none of the properties specified afterwards will be followed.
Here are my final chunks:
outer:
<h6 align="center">GetRelated Title</h6>
<ul class="relatedul">
[[+wrapper]]
</ul>
Silly to use the h6 here for a custom title, but I will change it later.
row:
<li>
<a href="[[~[[+id]]]]" title="[[+pagetitle]]">
[[+pagetitle]]
</a>
</li>
Here, I didn't want the title and long title appearing in the links, as I wanted the links to be short and sweet, so I cut some of the default template code out.
Finally, my glorious css:
div.related{
width: 70%;
margin: 0px auto 0px auto;
}
ul.relatedul{
padding:0px;
margin-left:20px;
list-style-position:outside;
}
ul.relatedul li{
float:left;
padding:0px 10px 0px 10px;
margin:0;
width:45%;
display:inline;
}
ul.relatedul li a{
background:url(list_arrow2.png) no-repeat 0 0;
color:#2282dc;
text-decoration:none;
display:block;
padding-left:15px;
font-size:12px;
}
ul.relatedul li a:hover{
background:url(list_arrow1.png) no-repeat 0 0;
text-decoration:underline;
color:#18b9ff;
}
The div is now centered in the containing div, and the li's are short enough to allow for two columns, but if the title is too long, then things will look less than beautiful, so I have been editing titles today.
Still got one issue, before I was able to put a border around the whole thing, but later I couldn't, I think its related to the display:inline and display:block lines, but that's a minor thing that I may or may not fix.
Another minor point, the documentation says that the default templates are in assets/components, but they aren't there in my install (Revo version 2.2.7). This seemed to be a problem at first, but once I specified my own templates, the defaults were gone and there was no need to mess with them.
Ok, I am off to implement this! Thanks to Mark and everyone who helped!