I'm glad! ^_^
I can offer some basic guidance, but it will never be as good as getting a specialist consultant with relevant lived experience (e.g. visual impairment, Irlen Syndrome, dyslexia...) to look over the specific document in question, so please bear that in mind. With that said, brace yourself for an infodump!
The Centre for Excellence in Universal Design suggests that you avoid placing background images behind text and use a line-height of at least 1.5 times the text size – this provides enough ‘breathing space’ for users to be able read text comfortably. (Source: https://universaldesign.ie/communications-digital/web-and-mobile-accessibility/w... )
Minimum default 'clear print' font size is 12pt, but bigger is better - especially for people with visual impairments. Consider making a large-print version if possible - that's 16pt Arial or bigger. For a beginner-friendly checklist, see https://www.sensorytrust.org.uk/resources/guidance/designing-with-clear-and-larg... and for more in-depth information on clear and large print standards, see the guidance documents here: https://www.ukaaf.org/service/large-print/
For a more thorough technical breakdown of reader-friendly design choices for dyslexia, including good typefaces to use, see the British Dyslexia Association's style guide: https://www.bdadyslexia.org.uk/advice/employers/creating-a-dyslexia-friendly-wor...
When selecting a background colour for digital display, aim for off-white/cream as a default - this is more accessible for people with Irlen Syndrome than white, but still allows for personalised coloured filters to be used over the top if needed. If you want to go the extra mile, you can provide a variety of versions using the different colours that are recommended by experts - see the row of pastel-coloured glasses icons at the top of this website for examples. https://irlen.com/
To create a printer-friendly version, remove the tinted background so you just have black text for the printer to focus on. (People may have their own coloured paper of choice, and nobody wants to waste colour ink or wind up with unwanted greyscale backgrounds.)
For guidance on margin sizing in digital media, you can try https://uxmovement.com/content/how-margins-and-line-lengths-affect-readability/ to help you get started
It's always good to make sure that your PDFs are screen-reader friendly (see this guidance for a thorough walkthrough https://www.gov.wales/how-create-accessible-pdf-documents).
However, for poetry - and especially when the creator is a performance poet, with the skills to do their work justice - an even better option is to record an audio file that delivers the work as intended, rather than trusting to the text-to-speech of a screen-reader, which can be quite 'robotic' and monotonous. There's some specific guidance for recording poetry available here: https://ypn.poetrysociety.org.uk/features/how-to-record-a-poem-like-a-pro/
I hope this is helpful! :)