Crocheting plarn with severe arthritis needing advice on how to crochet faster

I am making plarn sleeping mats for the homeless in my city. I have osteoarthritis and rheumatoid arthritis. I am using a size 16mm hook with a single crochet stitch, the sleeping mats are 35 stitches across 6ft approximately long. Is there a way to crochet faster? I want to keep the stitch the same because many use the mats during the day to block the sun so I don't want big holes. I'm not fast at all it takes me 120+ hours to make the plarn, and crochet it. I've only been able to make 8 complete mats with pillows in approximately 5 months. I make these when I can since my hands don't always work. If there are tricks or tips like different tools I can use or different ways of gripping I'd greatly appreciate it.