Trail Running Packs

[swash]

I'm currently looking into a new pack for trail running. I've had the High Sierra Soaker 70 pack for a couple of years and have used it on day hikes but never for running. It's small and light and has just enough room to put snacks in it and even a small first aid kit, etc. I like this pack a lot but I need to buy a new bladder for it (poor maintenance) and the specific bladders for this pack are getting harder to find. That got me thinking about buying a new pack for trail running. I've been looking at the CamelBak cloud walker 70 fl oz. 20 liter pack and the REI stoke 70 fl oz. 19 liter pack. I know these are a little big for trail running but they are light (both 1.2 pounds) and I would use them as my new day pack (I'm all about sacrificing some weight/size to use one purchase for multiple activities). Does anyone have experience with either of these packs, and what packs does everyone else use for trail running?

EDIT: I've decided to buy a replacement bladder for my high sierra and getting one of the other packs as a day pack only. After thinking it through it seems like a pack that big wouldn't really suit a couple hours of running. I will try it out a couple times though just to see how I like it.