If you got 3rd in your first race, I should be asking you for tips.
most rentals have a brake that cancels the throttle, so you can add a little throttle, but not past a certain point. Some do brake without letting off the gas. Some of the karts just don’t have any grunt at the low end compared to others.
On the start it depends on what everyone else does, so I wouldn’t sweat over too much of a plan. A good bit of lick can be involved. In Bumper Karts is can take a few turns to sort out. Inside on one corner can turn into the outside on the next.
In the past my plan was
Plan A: Get out in front of the crash
Plan B: Sit back, watch the crash and drive by it as a rubber necker.
I think overall you need to manage the variables you can and don’t worry about what you can’t.
In our rental league the new guy running it went to lap times for qualifying as opposed to finish order. That is kind of nice as you can let the pack go and try to get a quick traffic free lap, but sometimes drafting is the way to go. Main thing I have found is just using the form up lap figuring out the individual kart you have and how it is acting.