Yes, you need a Vented bottle. Try holding a 2-liter bottle against your sink faucet. You'll get the idea quick. I'd say about 1/4" hole should do.
IMO, I'd wire that electric fan with a manual switch and/or another wire leading to one of those portable "Jump Starter" packs. So you can keep the fan going when needed. Then just pass off the battery pack to a friend at the start line without the added weight of an extra battery on board. Can even use a few of those batt packs if waiting time is longer.
Just my .02... Hope it helps