well, according to google you can tan in a few hours. let's assume that "a few" means about 3.
3*60 minutes is 180 minutes. 180* 60 seconds is 10,800 seconds. 10,800 divided by 3 seconds (for each pin) is 3,600 pins.
i know that sounds like a lot, but you could work a more meltzerbait style where you include numerous pinfall attempts to try and bump it down.
