Hey Mike.
Some good advise on here. With regards to the bobbin, if it is burrs, you will see it fray rather than snap. The 70 denier (8/0) is a tough thread to learn on because it does break easily. Once you get the feel for the tension you can give it before it breaks, it gets easy. You'll never not break thread, but just less of it. The 6/0 or 140 denier is good to learn with, but smaller flies it can be bulky. If you get a chance, come out to the Spruce Meadows show and stop by our booth. There will be a bunch of tyers there who will be happy to give you some help. Also, if you can, the Hook and Hackle club is a great idea, and a good place to pick up some new patterns.