I got some great feedback (thanks Patrick!) about the random quotes hack I built for Squarespace, based on an issue with different templates in Squarespace - in some templates such as Dovetail, the random quotes didn't function.
I had assumed the template base structure would be very similar across all templates but it appears there are small differences in the block naming being used.
I used the "content" block (a DIV id) in the Bedford template but that didn't appear in the Dovetail, however. After some comparison both had a parent block named "page" and the code was changed and tested successfully on both.
The code has been updated in the original post (since answers.squarespace.com links there and in my git repo: