Just a point on the color of balls. They change often depending on what is aboard the boat maintaining the balls. If they are replacing a red ball and only have yellow on board it becomes a yellow ball.
The 90 minute limit is correct on all the balls. It's annoying to be waiting for a dive ball and watch the people on the ball eating lunch or sunbathing hours after they pick it up. If someone is waiting I get off the ball ASAP. You can eat lunch drifting or underway. I also make sure the first boat waiting gets my ball when I leave. It amazes me how rude someone can be trying to snake a ball when someone else has been waiting.
G