What is your arrow weight now? I am not a big advocate of speed unless your shooting a 3D setup. I am however, a huge advocate of getting the most kinetic energy as possible out of a setup and finding the perfect balance of k/e and speed. A lighter weight arrow will give you more speed, but it also carries less k/e downrange�the lighter the arrow, the quicker it looses energy and speed. Finding that perfect balance of speed and energy is what you should try to achieve.

As far as accuracy, that really depends on the spine of the arrow. Moving away from the ideal spine can affect arrow flight, which can lead to accuracy issue.