Have you found that in anything but black or white? I don't use those colors.

I always use the same weight and fibre on the top and in the bobbin for quilting piecing. I don't want something breaking from a stronger thread sawing through a weaker one or puckering from uneven shrinkage. But for quilting, anything goes.

Do you mean the it is now acceptable to sew cotton with poly thread? Piecing or quilting?

When I first started quilting, many years ago, I sewed everything with the old C&C cotton covered poly. I made small "quilts" that I used to cover the furniture seats. My husband sat on his on his recliner for years...probably 10 or more. ONE quilt square started to deteriorate and I just covered that with another square and ZZd around it. I'd say that wore very well under heavy use.

I use 60wt cotton in my bobbins for piecing, don't have to refill the bobbins so often that way. Haven't had any problems with doing this. A friend of mine has been doing this for years.

When I bought my Janome 6600, the dealer told me to use Bottom Line in the bobbin. It is 60 wt. poly. It does a terrific job. I usually buy it from Superior threads. I use it for piecing and quilting with no problem.

I use pre-wound 60# for my FW for piecing. I get them on Ebay 144 for $10.00. They are super. Black and white and I have found them From Marathon in the primary colors. 12 for about $5.00