A: No. The 64-bit version simply allows your program to use more memory. There is no real advantage to 64-bit unless you want to fetch a one-billion-row table all into memory on your PC within a Toad data grid. Keep in mind that your version of Toad should match your version of Oracle client (32-bit/64-bit).
Chris Reyes previously worked for Quest and Dell managing the Toad World site and Program Management for various Toad applications. In my spare time, I like to play vintage base ball (1880's rules) and do 3D printing.