for machine quilting, my go-to threads are Permacore and Omni. Omni is a poly wrapped cotton just like the perma core ( or is that cotton wrapped poly?). Any how, I like them both. They are not very heavy..and not too thin. the Omni is a new line from Superior Threads and has a bit more of a sheen. They come in scads of colors. Permacore is a bit cheaper.