Using both modifiers seems bit harsh. Friend of mine suggested that passing & fumbling modifiers would be applied in two parts. So that only TZ's affect fumbling and TZ's and pass lenght accuracy.
- Let's say you normally throw dice and get 4 and you are tring to throw long bomb and there is one opponent TZ affecting the thrower. Getting -2 from long bomb and -1 from one TZ would cause fumble.
- New way of handling this would go like this: You have rolled 4 and because of one TZ that is reduced to 3. At this point the fumbling is checked, since after modifier it's more than 1, and the pass is thrown. Now we deduct modifiers caused by pass lenght from the three and get 1. This doesn't anymore cause fumble but a inaccurate pass, unless the thrower happens to have AG of 6.
Hope you can make out what I'm trying to say here...

And I hope that I have understood throwing correctly...