I've never even tried offering thawed pinkies, always heard that tarantulas need something that moves to be interested in eating it.
As for fuzzies being dangerous to your T, that is very unlikely. Tarantulas are surprisingly good predators and adults T's can overcome and kill an adult mouse. But DON'T give your T a full grown mouse. Aside from being obviously dangerous as the mouse could inflict severe damage on the T, it would also be way too big of a meal.
Now this I'm really not sure on and won't believe until it's corroborated by a more reliable source but I was told that if you would give an extraordinarily large prey item to your T, it could eat until it's abdomen burst. Truth or fiction? I don't know and don't tend to believe it. Anyways, I never give prey that is too large so it's never going to be a problem for me!!!
As for up to what size of fuzzies you can give your T, that depends mostly on the size of your T. My general rule of thumbs are:
2 1/2" to 3" legspan: small pinkies.
3" to 5": med pinkies to small fuzzies.
5" and +: med fuzzies
I don't have any T's that surpass 5 1/2" legspan but I would imagine that a very large T (7" and more) could easily handle a large fuzzy. I would see no need to ever go to hoppers. I'd rather give 2 fuzzies if I had a T that was that hungry but that would have to be one reaaaallllyy hungry tarantula!!!
Hope this helps
Pixie
P.S. Getting a new T tomorrow
I can't wait!!! I'm not saying what kind yet, I'll post pics when I get her!!!