[Knufire]

1. You're fine during acceleration; the motor is only stalled for an instant. You can see here from the 40A breaker datasheet that you can draw large amounts of currents for a short amount of time. You really just want to avoid any scenarios where you would be stalled for an extended period of time (a head-to-head pushing match where neither robot breaks traction, stalled against a wall, etc).

2. Max speed is a bit of a misnomer. Opinion on the ideal top speed varies greatly with team and with region. It is obviously beneficial to go faster, but there are drawbacks. The higher your top speed is, the slower you will accelerate. In addition, you'll draw more current, meaning you need to pay more attention to your wiring, battery charging, and battery health in order to minimize resistance before the motor.

The best advice I can give you is this; there are various robot acceleration models floating around on Chief Delphi. Based on the game and your strategy, pick a distance that you think would be the most traveled (e.g. from the edge of the defenses to the low goal) and pick your gear ratio to minimize the time to go this distance.