Don't know what the optimum pressure is for the gas. This pressure varies with temperature. this is why we give you the gas adjust parameter. As far as removing the gas can after start, You could leave it out all together. If you use the trigger valve we sell, you can push up the trigger and the gas will stay on. Simply hook it up in place of the gas tank by using a straight Festo fitting.After the engine starts, lower the trigger and disconnect the line. The solenoid will close automatically.