Thanks to everyone who has shared their input so far! Going to try the different samples this weekend, hopefully ... and also going to read up a lot more about poly threads. I think they'd be great for art quilts, but this is going on my bed & due to asthma, I will likely be washing the quilt at least every 2 months, possibly even once a month, in commercial machines so I need something that's going to hold up. I haven't had good luck with synthetic threads & regular washing in the past (had to re-quilt my table runner & that was washed much less), but I'm sure part of the issue was I wasn't using a quality brand. I've also accidentally melted embroidery work so I'll have to learn more about wet blocking rather than steam blocking my quilt. Ugh! So much to learn!
Thank you again to all of you for taking so much time to respond & provide so much helpful information!