AFAIK, there is NO maximum bonus. It might cap out at 256^2-1, but that is absurdly high.
The 99% is the maximum to hit, not the max bonus. All modifiers are added together (including range to target), and then if the chance to hit exceeds 99, it is lowered to 99. But, the Talisman makes it 100 no matter what modifiers are in play, which is what makes it inherently unbalanced.