No. Don't fast charge LiPo's. Charge at 1 C or lower. (take the mAh of the pack and divide by 1000 to get the 1C rating of the pack...i.e. 1100mAh = 1C of 1.1A. Charge at 1.1A or lower.)
In practice it won't take an hour...since they're usually not completely dead and you're just topping it up.
But yes...if you're charging 4 batteries it could take 4 hours. Start earlier, the day before, rotate through your batteries...etc... (not at 2am for a 8am start time for game day
)
How long it'll last in your gun with your shooting style is hard to tell....measure before using, use, measure, use, measure, use and get a sense of how long it's lasting. It'd be completely different for a different rifle.
I suppose you could measure it accurately and calculate how much power each shot is drawing...if you figure that out come figure it out for my gun too.