oil capcity and drain time restrictions

I would trust your owner's manual but when you change oil next time, stop adding oil after about 5 quarts, start the truck so the filter fills, and then stop the engine and pull the dipstick and see what it reads. Then slowly add more oil until it registers "full" and see how much, total, you put in. Full drain only takes a few minutes so "under 10 minutes" is a good guess.

The longer the drain time the better. I drain oil for as long as practical (until it is just dripping a little). Get rid of as much of the dirty oil as you can. The cleaner your engine is the better!