I had a 770, and agree that it would be happy with just about any thread. Not picky at all. You usually use that fine weight bobbin thread when you are actually doing an embroidery design, which is pretty dense. You will probably want to get prewound NEBs (National Embroidery Bobbins) are probably the most common. With less dense designs, you can use a bit heavier weight thread in the bobbin.
I also agree with Cari in that using a machine with that small area for quilting a large quilt is going to be difficult (although there are folks who do it all the time). I was only successful in doing borders where most of the quilt was outside the harp. I also did a couple of QAYG, where you quilt the blocks individually then join.
We have a specific thread for ME, you can check there too:
https://www.quiltingboard.com/main-f...un-t32969.html