For very dense quilting, I'd use 50 or 60 weight. My LA needed Tex 40. My thinking is leaning toward poly due to the strength over cotton. For very obvious quilting that's not dense, I like 30 or higher weight. Does any of that help? And then, sometimes, I use whatever. It's a hobby for fun. Life has enough stress.
Then there's competition quilting..... that's totally different.