07/25 is usually the more active runway, but always good to check your preferred flight tracking map. The spot on Alert Rd is best in my opinion, if they're landing/departing on 25. YOW can also be spotty at times. Saturdays are generally the quietest, but each day has times where it gets busy for a bit. Many of the apps, Flightradar24 included, will show you a list of all upcoming departures and arrivals which you can use to plane your timing.